OpenAtlas

There are some warnings in the apache2 error logs that are from libvips or wand. It is hard to track, from which especially it happen at this time: [Thu Apr 09 00:30:38.643440 2026]

Here are some expamles:

JPEGLib: Warning, Corrupt JPEG data: premature end of data segment.
JPEGLib: Invalid JPEG file structure: two SOI markers.
JPEGLib: Not a JPEG file: starts with 0x11 0x00.
JPEGFixupTagsSubsampling: Warning, Unable to auto-correct subsampling values, likely corrupt JPEG compressed data in first strip/tile; auto-correcting skipped.
JPEGFixupTagsSubsamplingSec: Warning, Subsampling values inside JPEG compressed data have no TIFF equivalent, auto-correction of TIFF subsampling values failed.
TIFFReadDirectory: Cannot handle different values per sample for "SampleFormat".
ZIPDecode: Decoding error at scanline 640.
JPEGLib: Warning, Premature end of JPEG file.
TIFFReadDirectory: Cannot handle different values per sample for "BitsPerSample".

I checked our file conversion, resize and convert to iiif, and there is basically only a file extension check, which is not sufficient (I can also save a JPG as .txt). We could use python3-magic to check the real file header instead.

Maybe it is also worth checking if resize and convert can be merged.