Fix webp fallback

[Tweekazoid]

assets may say they have webp.
but that images is often "access denied"

[codecov]

Codecov Report

❌ Patch coverage is 6.66667% with 28 lines in your changes missing coverage. Please review.
✅ Project coverage is 34.19%. Comparing base (eddefa6) to head (fd8c6b9).

Files with missing lines	Patch %	Lines
search.py	6.66%	28 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2310      +/-   ##
==========================================
- Coverage   34.21%   34.19%   -0.02%     
==========================================
  Files          87       87              
  Lines       27581    27601      +20     
==========================================
+ Hits         9436     9438       +2     
- Misses      18145    18163      +18     

Flag	Coverage Δ
python	34.19% <6.66%> (-0.02%)	⬇️

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Files with missing lines	Coverage Δ
search.py	26.28% <6.66%> (-0.24%)	⬇️

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