A bit of history GIF is the oldest widespread compressed image format. Today, it is mostly famous for allowing animations in an image file, but I am not so interested in that use. Actually, it turns out this was the only image format ever supported by NCSA Mosaic. Your website must have a GIF fallback for all critical images if it ever wants to truly support old browsers. I’m not talking old as in old Chromium. I mean actual Mosaic, Netscape, IE, Netsurf, Dillo, Konqueror - like those you can...