The scanned file that just won't open
You receive a scanned document or a professional photo file, double-click it or drag it into a browser tab expecting a preview, and nothing happens — or the browser tries to download it instead of showing it. Check the extension and it's usually .tiff or .tif, a format that's completely standard in scanning and print workflows but has one specific gap: no major browser has ever added native TIFF support, unlike JPEG, PNG, WebP, and even the newer AVIF format.
This isn't a corrupted file or a bug on your end — it's simply a format the web was never built to display directly.
Where TIFF actually comes from
TIFF didn't disappear from professional workflows — it's still the default output for many document scanners, and it remains popular in professional photography and print production because it can store images losslessly at very high quality, without JPEG's compression artifacts. That makes it the right internal working format for a print shop or a professional photographer, but the wrong format to hand to someone who just needs to view or share the file normally.
So the file you've received isn't wrong — it's just meant for a different stage of a workflow than "open it and look at it in a browser."
What actually has to happen to convert it
Since browsers can't decode TIFF, converting it requires a dedicated TIFF parser that reads the format's internal structure directly rather than relying on any built-in browser image support. TIFF files can also use different internal compression schemes — some are stored uncompressed, others use PackBits or LZW compression — and a converter needs to specifically understand whichever scheme a given file actually uses.
The two most common cases — uncompressed and PackBits-compressed TIFF, which cover the overwhelming majority of scanner and standard image-editing software output — convert cleanly. Less common schemes like LZW compression are a different, more complex case that not every browser-based converter handles.
What a clear error message actually means here
If a TIFF-to-JPG conversion fails with a message about unsupported compression, that's not a sign of a broken tool — it means the specific file uses an internal compression scheme the converter doesn't decode. A well-built converter reports this clearly rather than guessing and producing a corrupted or visually wrong image, which matters because a silently wrong image is worse than an honest failure you can act on (like re-exporting the TIFF with different settings from whatever produced it).