Image/Thumbnail Problems: Thumbnails not working for GIF animations

Discussion in 'Main Site and Forum Support' started by Dreit, Feb 12, 2017.

  1. Dreit

    Dreit Czech dragon

    My girlfriend was just uploading GIF animation to FA and we were fighting a lot with thumbnail generation.

    1) If she uploaded only GIF file, thumbnail generator used only last frame (transparency and difference from previous frame, default in nearly every software to save space) instead of proper image. I'm not sure which software FA uses, but for imagemagick there's option -coalesce which should solve this issue.

    2) Worse thing is, if she uploaded GIF and separated JPEG thumbnail file, FA preferred generated thumbnail over uploaded one.

    We solved it by making animation in imagemagick with option -dispose none which makes working thumbnail, but pretty big files. If I try to search for "gif" on FA, it actually shows few of those broken thumbnails on art of various users, so it surely happened to more users.
  2. jayhusky

    jayhusky Well-Known Member

    True FA does have some issues with rendering gif thumbnails, and from what is known FA does use IM to generate its thumbs.
    However it can be bypassed by uploading a custom thumbnail and forcing your cache to clear. 99% of the time a image that doesn't change after upload is a cache issue.

    In FA's case, the system will always take preference of a custom thumbnail (when provided), over a rendered one.
  3. quoting_mungo

    quoting_mungo Well-Known Member

    Yes and no - unfortunately custom thumbnails are only supported at certain sizes, so any page that uses a different sized thumbnail will still use an auto-generated one. At the moment, disabling the GIF compression that stores only changed image information is really the only way to get thumbnails/previews to work at all sizes for animated GIFs.
  4. jayhusky

    jayhusky Well-Known Member

    Ah ok.

    Would it be possible for a tutorial to be written up by staff and linked to from the upload section of the site? (Sort of a helpful hint tooltip/link?)
  5. Dragoneer

    Dragoneer Administrator Staff Member

    Eventually, yes, but custom thumbnails need to be completely re-written. It's something we're working on, but I don't have an ETA.
    jayhusky likes this.
  6. Dreit

    Dreit Czech dragon

    Thanks for replies everybody.
    It sounds like whole thumbnail generation is overcomplicated o.o I'd expect simple "if thumbnail_file; then use_thumnail_file; else use_original_picture". Or taking first frame from GIFs instead of last one.

    That reminds me joke about software which runs correctly only at saturday :)
  7. Dragoneer

    Dragoneer Administrator Staff Member

    Just updating this -- we are actively working on fixing the gif thumbnail system, and our fix is currently in testing.
  8. Dreit

    Dreit Czech dragon

    *just finished reading journal*
    So much happiness in comments, aww! I think it was worth it ;)

Share This Page