diff --git a/.github/workflows/validate-site.yml b/.github/workflows/validate-site.yml
new file mode 100644
index 0000000..1659c62
--- /dev/null
+++ b/.github/workflows/validate-site.yml
@@ -0,0 +1,20 @@
+name: Validate site data
+
+on:
+  pull_request:
+  push:
+    branches: [master]
+
+permissions:
+  contents: read
+
+jobs:
+  validate:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
+      - name: Validate CSV and asset contracts
+        run: python scripts/validate_site.py
\ No newline at end of file
diff --git a/MAINTAINER_CHECKLIST.md b/MAINTAINER_CHECKLIST.md
new file mode 100644
index 0000000..cadc66b
--- /dev/null
+++ b/MAINTAINER_CHECKLIST.md
@@ -0,0 +1,29 @@
+# VICE Lab Website Maintainer Checklist
+
+## Photos requiring human follow-up
+
+Before adding a portrait, confirm the subject approves its use and that VICE Lab has permission to publish it. Use a square or portrait-oriented JPEG, crop consistently with existing headshots, optimize it for the web, and use the exact filename shown.
+
+- [ ] Obtain an approved portrait for Erin Hestir and save it as `images/people/erin-hestir.jpg`.
+- [ ] Obtain an approved portrait for Aditya Sood and save it as `images/people/aditya-sood.jpg` (used by the Sierra HP and CERC-WET projects).
+- [ ] Obtain an approved portrait for Megan Mayzelle and save it as `images/people/megan-mayzelle.jpg`.
+- [ ] Confirm that `images/people/josue-medellin-azuara.jpg` is the intended current portrait for the Water Systems Management collaborator card.
+- [ ] Review collaborator names and affiliations against their official lab pages at least annually.
+
+Until these photographs are supplied, the site displays `images/people/no-picture.jpg` instead of a broken image.
+
+## Content decisions
+
+- [ ] Decide whether the 2021 Community Survey page should be updated, archived, or removed; it still promises a June 2021 report.
+- [ ] Update the footer's “Updated October 2020” wording or replace it with an automatically maintained copyright year.
+- [ ] Review and update remaining plain-HTTP external links.
+- [ ] Confirm whether the archived PPIC site snapshot should remain publicly deployed under `archived-sites/`.
+- [ ] Review people referenced by projects, news, and publications but absent from `people.csv`; either add profiles or intentionally render their names without profile links.
+
+## Technical follow-up
+
+- [ ] Upgrade the bundled jQuery 3.3.1 to a supported release and regression-test CSV rendering, menus, filters, and modals.
+- [ ] Compress `images/news/casa-ele-2022-launched.jpg` (currently about 21.7 MB) and other multi-megabyte images; target less than 500 KB where practical.
+- [ ] Confirm whether the unused `images/news/IMG_0383.png` can be removed.
+- [ ] Add a periodic external-link checker after redirects and intentionally archived links are documented.
+- [ ] Run `python scripts/validate_site.py` before every content pull request and resolve all errors; review warnings explicitly.
\ No newline at end of file
diff --git a/collaborators/index.html b/collaborators/index.html
index 4bcecea..7c075d1 100644
--- a/collaborators/index.html
+++ b/collaborators/index.html
@@ -121,7 +121,8 @@ <h2>
 						default:
 							people_data= '';
 							if (data[i].AUTHOR != "") {
-								people_data = '<div class="meta"><a href="people" class="author"><span class="name">' + data[i].AUTHOR.replace("-", " ") + '</span><img src="/images/people/' + data[i].AUTHOR + '.jpg" alt="" /></a></div>'
+								var authorImage = data[i].AUTHOR === "josue-medellin" ? "josue-medellin-azuara" : data[i].AUTHOR;
+								people_data = '<div class="meta"><span class="author"><span class="name">' + data[i].AUTHOR.replaceAll("-", " ") + '</span><img loading="lazy" src="/images/people/' + authorImage + '.jpg" onerror="this.onerror=null;this.src=\'/images/people/no-picture.jpg\'" alt="' + data[i].NAME + ' collaborator portrait" /></span></div>'
 							}
 							$("#collaborators").append(
 								$.parseHTML(
@@ -130,6 +131,8 @@ <h2>
 							break;
 					}
 				}
+			}).fail(function () {
+				$("#collaborators").append("<p>Unable to load collaborators right now. Please try again later.</p>");
 			});
 			/*Footer: Controlled by HTML snippet in snippets/footer.html*/
 			$("#footer").load("../snippets/footer.html");
diff --git a/images/news/USDA-SWF-on-NPR.jpg b/images/news/usda-swf-on-npr.jpg
similarity index 100%
rename from images/news/USDA-SWF-on-NPR.jpg
rename to images/news/usda-swf-on-npr.jpg
diff --git a/images/projects/cosumnes.jpg b/images/projects/Cosumnes.jpg
similarity index 100%
rename from images/projects/cosumnes.jpg
rename to images/projects/Cosumnes.jpg
diff --git a/index.html b/index.html
index 01e9dd8..7c886b3 100644
--- a/index.html
+++ b/index.html
@@ -164,7 +164,7 @@ <h2>
 
 			$.get("/news.csv").then(function (text, status, xhr) {
 				var data = $.csv.toObjects(text);
-				for (var i = 0; i < NUMBER_FRONT_PAGE_NEWS; i++) {
+				for (var i = 0; i < Math.min(NUMBER_FRONT_PAGE_NEWS, data.length); i++) {
 					switch (data[i].ID) {
 						default:
 							$("#news").append(
@@ -172,22 +172,24 @@ <h2>
 									'<article class="post">' +
 										'<header>' +
 											'<div class="title">' +
-												'<h2><a href="/news">' + data[i].NAME + '</a></h2>' + 
+												'<h2><a href="/news">' + data[i].NAME + '</a></h2>' +
 											'</div>' +
 											'<div class="meta">' +
-												'<time class="published" datetime="2015-11-01">' + data[i].DATE + '</time>' +
-												'<a href="/people" class="author"><span class="name">' + data[i].AUTHOR.replace("-", " ") + '</span><img src="/images/people/' + data[i].AUTHOR + '.jpg" alt="" /></a>' + 
+												'<time class="published">' + data[i].DATE + '</time>' +
+												'<a href="/people" class="author"><span class="name">' + data[i].AUTHOR.replaceAll("-", " ") + '</span><img loading="lazy" src="/images/people/' + data[i].AUTHOR + '.jpg" onerror="this.onerror=null;this.src=\'/images/people/no-picture.jpg\'" alt="' + data[i].AUTHOR.replaceAll("-", " ") + '" /></a>' +
 											'</div>'+
 										'</header>' +
 										'<div style="display: block; overflow: auto">' +
-											'<img style= "margin: 0 1em 1em 0; float:left; width: 35%;" class="image featured" src="/images/news/' + data[i].ID + '.jpg" alt="" />' +
+											'<img loading="lazy" style= "margin: 0 1em 1em 0; float:left; width: 35%;" class="image featured" src="/images/news/' + data[i].ID + '.jpg" alt="' + data[i].NAME + '" />' +
 											'<p style="margin:0;">' + data[i].TEXT + '</p>' +
-										'</div>' + 
+										'</div>' +
 									'</article>'
 								));
 							break;
 					}
 				}
+			}).fail(function () {
+				$("#news").append("<p>Unable to load news right now. Please try again later.</p>");
 			});
 			$.get("/projects.csv").then(function (text, status, xhr) {
 				var data = $.csv.toObjects(text);
@@ -200,11 +202,13 @@ <h2>
 							break;
 						default:
 							$("#projects").append(
-								$.parseHTML('<article class="mini-post"><header><h3><a href="/projects">' + data[i].NAME + '</a></h3><time class="published" datetime="2015-10-18">' + data[i].DATE + '</time><a href="/people" class="author"><img src="/images/people/' + data[i].AUTHOR.split(";")[0] + '.jpg" alt="" /></a></header><a href="/projects" class="image"><img src="images/projects/' + data[i].ID + '.jpg" onerror="this.onerror=null;this.src=\'/images/projects/' + data[i].ID + '.svg\'" alt="" /></a></article>'
+								$.parseHTML('<article class="mini-post"><header><h3><a href="/projects">' + data[i].NAME + '</a></h3><time class="published">' + data[i].DATE + '</time><a href="/people" class="author"><img loading="lazy" src="/images/people/' + data[i].AUTHOR.split(";")[0] + '.jpg" onerror="this.onerror=null;this.src=\'/images/people/no-picture.jpg\'" alt="' + data[i].AUTHOR.split(";")[0].replaceAll("-", " ") + '" /></a></header><a href="/projects" class="image"><img loading="lazy" src="images/projects/' + data[i].ID + '.jpg" onerror="if(this.dataset.fallback){this.onerror=null;this.src=\'/images/people/no-picture.jpg\';}else{this.dataset.fallback=\'1\';this.src=\'/images/projects/' + data[i].ID + '.svg\';}" alt="' + data[i].NAME + '" /></a></article>'
 								));
 							break;
 					}
 				}
+			}).fail(function () {
+				$("#projects").append("<p>Unable to load projects right now. Please try again later.</p>");
 			});
 		});
 	</script>
diff --git a/news/index.html b/news/index.html
index cf2f100..5644276 100644
--- a/news/index.html
+++ b/news/index.html
@@ -121,20 +121,22 @@ <h2>
 							'<article class="post">' +
 								'<header>' +
 									'<div class="title">' +
-										'<h2 id ="' + data[i].ID + '">' + data[i].NAME + '</h2>' + 
+										'<h2 id ="' + data[i].ID + '">' + data[i].NAME + '</h2>' +
 									'</div>' +
 									'<div class="meta">' +
-										'<time class="published" datetime="2015-11-01">' + data[i].DATE + '</time>' +
-										'<a href="/people" class="author"><span class="name">' + data[i].AUTHOR.replace("-", " ") + '</span><img src="/images/people/' + data[i].AUTHOR + '.jpg" alt="" /></a>' + 
+										'<time class="published">' + data[i].DATE + '</time>' +
+										'<a href="/people" class="author"><span class="name">' + data[i].AUTHOR.replaceAll("-", " ") + '</span><img loading="lazy" src="/images/people/' + data[i].AUTHOR + '.jpg" onerror="this.onerror=null;this.src=\'/images/people/no-picture.jpg\'" alt="' + data[i].AUTHOR.replaceAll("-", " ") + '" /></a>' +
 									'</div>'+
 								'</header>' +
 								'<div style="display: block; overflow: auto">' +
-									'<img style= "margin: 0 1em 1em 0; float:left; width: 25%;" class="image featured" src="/images/news/' + data[i].ID + '.jpg" alt="" />' +
+									'<img loading="lazy" style= "margin: 0 1em 1em 0; float:left; width: 25%;" class="image featured" src="/images/news/' + data[i].ID + '.jpg" alt="' + data[i].NAME + '" />' +
 									'<p style="margin:0;">' + data[i].TEXT + '</p>' +
-								'</div>' + 
+								'</div>' +
 							'</article>'
 					));
 				}
+			}).fail(function () {
+				$("#news").append("<p>Unable to load news right now. Please try again later.</p>");
 			});
 			/*Footer: Controlled by HTML snippet in snippets/footer.html*/
 			$("#footer").load("../snippets/footer.html");
diff --git a/people/index.html b/people/index.html
index 009c2a7..c2a0e7c 100644
--- a/people/index.html
+++ b/people/index.html
@@ -120,7 +120,7 @@ <h3 id="modal-title" style="margin:3em; color:white">
 	<script src="../assets/js/util.js"></script>
 	<script src="../assets/js/main.js"></script>
 	<script>
-		var data, news_data, project_data, publication_data;
+		var data = [], news_data = [], project_data = [], publication_data = [];
 
 		var modal = document.getElementById('people-modal');
 		modal.style.display = "none";
@@ -129,16 +129,22 @@ <h3 id="modal-title" style="margin:3em; color:white">
 
 		function loadModal(id) {
 			if (id != '') {
-				if (!getInfo(id)) { modal.style.display = "none"; window.location.hash = ""; return; }	// stale/unknown person id: do not crash
+				var personInfo = getInfo(id);
+				if (!personInfo) { modal.style.display = "none"; window.location.hash = ""; return; }	// stale/unknown person id: do not crash
 				modal.style.display = "block";
 				var logo = document.getElementById('modal-image');
 				logo.src = '/images/people/' + id + '.jpg';
+				logo.alt = personInfo.NAME;
+				logo.onerror = function () {
+					this.onerror = null;
+					this.src = '/images/people/no-picture.jpg';
+				};
 				var name = document.getElementById('modal-name');
-				name.innerHTML = getInfo(id).NAME;
+				name.textContent = personInfo.NAME;
 				var title = document.getElementById('modal-title');
-				title.innerHTML = getInfo(id).TITLE;
+				title.textContent = personInfo.TITLE;
 				var biography = document.getElementById('modal-biography');
-				biography.innerHTML = getInfo(id).BIOGRAPHY + '<hr>'; 
+				biography.innerHTML = personInfo.BIOGRAPHY + '<hr>';
 
 				if (id == "josh-viers") {
 					biography.innerHTML += '<ul class="actions fit"><li><a href="/news" class="button fit">News</a></li><li><a href="/projects" class="button fit">Projects</a></li><li><a href="/publications" class="button fit">Publications</a></li><li><a href="/people" class="button fit">People</a></li><li><a href="/collaborators" class="button fit">Collaborators</a></li></ul>';
@@ -224,33 +230,38 @@ <h3 id="modal-title" style="margin:3em; color:white">
 									$("#people").append(
 									$.parseHTML(
 										'<a href= "#' + data[i].ID + '">' +
-										'<div style="display:inline-block;width:15em;height:100%;"><img class="image featured" style="margin: 0 0 1em 0; height: 240px; width: 240px;" src="/images/people/' + data[i].ID + '.jpg" alt=""/><center><h2 style="height:4em">' + data[i].NAME + '</h2\><br><h3>' + data[i].TITLE + '</h3><ul class="icons">' + email_html + twitter_html + github_html + '</ul></center></div>' +
+										'<div style="display:inline-block;width:15em;height:100%;"><img loading="lazy" class="image featured" style="margin: 0 0 1em 0; height: 240px; width: 240px;" src="/images/people/' + data[i].ID + '.jpg" onerror="this.onerror=null;this.src=\'/images/people/no-picture.jpg\'" alt="' + data[i].NAME + '"/><center><h2 style="height:4em">' + data[i].NAME + '</h2><br><h3>' + data[i].TITLE + '</h3><ul class="icons">' + email_html + twitter_html + github_html + '</ul></center></div>' +
 										'</a> '
 									));
 								}else{
 									$("#people").append(
 									$.parseHTML(
 										'<a href= "#' + data[i].ID + '">' +
-										'<div style="display:inline-flex; flex-wrap: wrap;width:15em;height:100%;"><img class="image featured" style="margin: 0 0 1em 0; height: 240px; width: 240px;" src="/images/people/' + data[i].ID + '.jpg" alt=""/><center><h2 style="height:4em">' + data[i].NAME + '</h2\><br><h3>' + data[i].TITLE + '</h3><ul class="icons">' + email_html + twitter_html + github_html + '</ul></center></div>' +
+										'<div style="display:inline-flex; flex-wrap: wrap;width:15em;height:100%;"><img loading="lazy" class="image featured" style="margin: 0 0 1em 0; height: 240px; width: 240px;" src="/images/people/' + data[i].ID + '.jpg" onerror="this.onerror=null;this.src=\'/images/people/no-picture.jpg\'" alt="' + data[i].NAME + '"/><center><h2 style="height:4em">' + data[i].NAME + '</h2><br><h3>' + data[i].TITLE + '</h3><ul class="icons">' + email_html + twitter_html + github_html + '</ul></center></div>' +
 										'</a> '
 									));
 								}
-								
+
 							}
 							break;
 					}
 				}
 
 				loadModal(window.location.hash.substring(1));
+			}).fail(function () {
+				$("#people").append("<p>Unable to load people right now. Please try again later.</p>");
 			});
-			$.get("/news.csv").then(function (text, status, xhr) {
-				news_data = $.csv.toObjects(text);
-			});
-			$.get("/projects.csv").then(function (text, status, xhr) {
-				project_data = $.csv.toObjects(text);
-			});
-			$.get("/publications.csv").then(function (text, status, xhr) {
-				publication_data = $.csv.toObjects(text);
+			$.when(
+				$.get("/news.csv"),
+				$.get("/projects.csv"),
+				$.get("/publications.csv")
+			).done(function (newsResponse, projectResponse, publicationResponse) {
+				news_data = $.csv.toObjects(newsResponse[0]);
+				project_data = $.csv.toObjects(projectResponse[0]);
+				publication_data = $.csv.toObjects(publicationResponse[0]);
+				loadModal(window.location.hash.substring(1));
+			}).fail(function () {
+				console.error("Unable to load related news, projects, or publications.");
 			});
 
 		});
diff --git a/projects/index.html b/projects/index.html
index 157bb56..57c0be9 100644
--- a/projects/index.html
+++ b/projects/index.html
@@ -141,7 +141,7 @@ <h2>Locations</h2>
 							var authors = data[i].AUTHOR.split(";");
 							var authors_html = '';
 							for (var j = 0; j < authors.length; j++) {
-								authors_html += '<a href="/people/#' + authors[j] + '" class="author"><span class="name">' + authors[j].replace("-", " ") + '</span><img src="/images/people/' + authors[j] + '.jpg" alt="" /></a>'
+								authors_html += '<a href="/people/#' + authors[j] + '" class="author"><span class="name">' + authors[j].replaceAll("-", " ") + '</span><img loading="lazy" src="/images/people/' + authors[j] + '.jpg" onerror="this.onerror=null;this.src=\'/images/people/no-picture.jpg\'" alt="' + authors[j].replaceAll("-", " ") + '" /></a>'
 							}
 							var tags = data[i].TAGS.split(";");
 							var tags_buttons_html = '';
@@ -167,16 +167,16 @@ <h2>Locations</h2>
 								if (!visited_locations.includes(locationArr[j])) {
 									visited_locations.push(locationArr[j]);
 									$("#locations").append(
-										'<a href="#" class="button" onclick="filterSelection(\'' + locationArr[j] + '\')">' + data[i].LOCATION.replace("-", " ") + '</a> '
+										'<a href="#" class="button" onclick="filterSelection(\'' + locationArr[j] + '\')">' + locationArr[j].replaceAll("-", " ") + '</a> '
 									);
 								}
 							}
 							location_html += '"';
 							$("#projects").append(
 								$.parseHTML(
-									'<article ' + tags_html + location_html + '><header><div class="title"><h2 id="' + data[i].ID + '">' + data[i].NAME + '</h3>' + tags_buttons_html + /*location_buttons_html + */ '</div><div class="meta"><time class="published" datetime="2015-11-01">' + data[i].DATE + '</time>' + authors_html + '</a></div></header>' +
+									'<article ' + tags_html + location_html + '><header><div class="title"><h2 id="' + data[i].ID + '">' + data[i].NAME + '</h2>' + tags_buttons_html + /*location_buttons_html + */ '</div><div class="meta"><time class="published">' + data[i].DATE + '</time>' + authors_html + '</div></header>' +
 									'<div style="display: block; overflow: auto">' +
-									'<img style= "margin: 0 1em 1em 0; float:left; width: 35%;" class="image featured" src="/images/projects/' + data[i].ID + '.jpg" onerror="this.onerror=null;this.src=\'/images/projects/' + data[i].ID + '.svg\'" alt="" />' +
+									'<img loading="lazy" style= "margin: 0 1em 1em 0; float:left; width: 35%;" class="image featured" src="/images/projects/' + data[i].ID + '.jpg" onerror="if(this.dataset.fallback){this.onerror=null;this.src=\'/images/people/no-picture.jpg\';}else{this.dataset.fallback=\'1\';this.src=\'/images/projects/' + data[i].ID + '.svg\';}" alt="' + data[i].NAME + '" />' +
 									'<p style="margin:0;">' + data[i].TEXT + '</p>' +
 									'</div>' +
 									'</article>'
@@ -184,17 +184,19 @@ <h2>Locations</h2>
 							break;
 					}
 				}
+			}).fail(function () {
+				$("#projects").append("<p>Unable to load projects right now. Please try again later.</p>");
 			});
 		});
 		filterSelection("all")
 		function filterSelection(c) {
 			var x, i;
 			//Needs each publication to have the tags be callable
-			x = document.getElementsByClassName("post");
+			x = document.querySelectorAll("#projects .post");
 			if (c == "all") c = "";
 			for (i = 0; i < x.length; i++) {
 				addElement(x[i], "hide");
-				if (x[i].className.indexOf(c) > -1) removeElement(x[i], "hide");
+				if (c === "" || x[i].classList.contains(c)) removeElement(x[i], "hide");
 			}
 		}
 		function addElement(element, name) {
diff --git a/publications/index.html b/publications/index.html
index 337a717..86ed8bb 100644
--- a/publications/index.html
+++ b/publications/index.html
@@ -228,10 +228,10 @@ <h3 id="${item.ID}">
 	});
 
 	function filterSelection(c) {
-		const posts = document.getElementsByClassName("post");
+		const posts = document.querySelectorAll("#publications .post");
 		Array.from(posts).forEach(post => {
 			post.style.display = "none";
-			if (c === "all" || post.className.includes(c)) {
+			if (c === "all" || post.classList.contains(c)) {
 				post.style.display = "block";
 			}
 		});
diff --git a/scripts/validate_site.py b/scripts/validate_site.py
new file mode 100644
index 0000000..7cc32c3
--- /dev/null
+++ b/scripts/validate_site.py
@@ -0,0 +1,118 @@
+#!/usr/bin/env python3
+"""Validate the CSV-to-asset contracts used by the VICE Lab static site."""
+
+from __future__ import annotations
+
+import csv
+import re
+import subprocess
+import sys
+from collections import Counter
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parents[1]
+CSV_SCHEMAS = {
+    "news.csv": ["ID", "NAME", "AUTHOR", "DATE", "TEXT"],
+    "projects.csv": ["ID", "NAME", "AUTHOR", "DATE", "TEXT", "TAGS", "LOCATION"],
+    "people.csv": ["ID", "NAME", "TITLE", "EMAIL", "TWITTER", "GITHUB", "BIOGRAPHY"],
+    "collaborators.csv": ["ID", "NAME", "AUTHOR", "LINK", "TEXT"],
+    "publications.csv": ["ID", "NAME", "AUTHOR", "LINK", "CITATION", "ABSTRACT", "DATE", "TAGS", "LOCATION"],
+}
+SECTION_IDS = {"RESEARCHERS", "AFFILIATES", "ALUMNI", "READ MORE"}
+SAFE_ID = re.compile(r"^[A-Za-z0-9][A-Za-z0-9-]*$")
+errors: list[str] = []
+warnings: list[str] = []
+tables: dict[str, list[dict[str, str]]] = {}
+tracked_result = subprocess.run(
+    ["git", "ls-files", "-z"],
+    cwd=ROOT,
+    check=True,
+    capture_output=True,
+    text=True,
+)
+tracked_files = {path for path in tracked_result.stdout.split("\0") if path}
+
+
+def error(message: str) -> None:
+    errors.append(message)
+
+
+def warn(message: str) -> None:
+    warnings.append(message)
+
+
+def authors(value: str) -> list[str]:
+    return [author.strip() for author in (value or "").split(";") if author.strip()]
+
+
+for filename, expected_header in CSV_SCHEMAS.items():
+    path = ROOT / filename
+    with path.open("r", encoding="utf-8-sig", newline="") as handle:
+        reader = csv.DictReader(handle)
+        if reader.fieldnames != expected_header:
+            error(f"{filename}: expected header {expected_header}, found {reader.fieldnames}")
+        rows = list(reader)
+    tables[filename] = rows
+    ids = [row.get("ID", "").strip() for row in rows]
+    for duplicate, count in Counter(ids).items():
+        if duplicate and count > 1:
+            error(f"{filename}: duplicate ID {duplicate!r}")
+    for line, row in enumerate(rows, 2):
+        if row.get(None):
+            error(f"{filename}:{line}: too many CSV columns")
+        item_id = row.get("ID", "").strip()
+        if not item_id:
+            error(f"{filename}:{line}: missing ID")
+        elif item_id not in SECTION_IDS and not SAFE_ID.fullmatch(item_id):
+            error(f"{filename}:{line}: unsafe ID {item_id!r}")
+
+for line, row in enumerate(tables["news.csv"], 2):
+    expected = f"images/news/{row['ID']}.jpg"
+    if expected not in tracked_files:
+        error(f"news.csv:{line}: missing exact-case image {expected}")
+
+for line, row in enumerate(tables["projects.csv"], 2):
+    if row["ID"] == "READ MORE":
+        continue
+    candidates = [f"images/projects/{row['ID']}.jpg", f"images/projects/{row['ID']}.svg"]
+    if not any(candidate in tracked_files for candidate in candidates):
+        error(f"projects.csv:{line}: missing exact-case image; expected one of {candidates}")
+    for author in authors(row.get("AUTHOR", "")):
+        portrait = f"images/people/{author}.jpg"
+        if portrait not in tracked_files:
+            warn(f"projects.csv:{line}: missing portrait {portrait}; site will use no-picture.jpg")
+
+for line, row in enumerate(tables["people.csv"], 2):
+    if row["ID"] in SECTION_IDS:
+        continue
+    portrait = f"images/people/{row['ID']}.jpg"
+    if portrait not in tracked_files:
+        warn(f"people.csv:{line}: missing portrait {portrait}; site will use no-picture.jpg")
+
+collaborator_image_aliases = {"josue-medellin": "josue-medellin-azuara"}
+for line, row in enumerate(tables["collaborators.csv"], 2):
+    author = row.get("AUTHOR", "").strip()
+    if not author:
+        continue
+    image_id = collaborator_image_aliases.get(author, author)
+    portrait = f"images/people/{image_id}.jpg"
+    if portrait not in tracked_files:
+        warn(f"collaborators.csv:{line}: missing portrait {portrait}; site will use no-picture.jpg")
+
+if "images/people/no-picture.jpg" not in tracked_files:
+    error("missing required fallback image images/people/no-picture.jpg")
+
+for path in ROOT.rglob("*"):
+    if (
+        path.is_file()
+        and path.relative_to(ROOT).as_posix() in tracked_files
+        and path.stat().st_size > 2_000_000
+    ):
+        warn(f"large file ({path.stat().st_size / 1_000_000:.1f} MB): {path.relative_to(ROOT).as_posix()}")
+
+for message in warnings:
+    print(f"WARNING: {message}")
+for message in errors:
+    print(f"ERROR: {message}", file=sys.stderr)
+print(f"Validated {sum(len(rows) for rows in tables.values())} CSV records: {len(errors)} error(s), {len(warnings)} warning(s).")
+sys.exit(1 if errors else 0)
\ No newline at end of file