When I enabled privacy.resistFingerprinting I see this error in the console:
Blocked https://www.inaturalist.org/observations/upload from extracting canvas data because no user input was detected
I don’t see that when it’s disabled. Reading up on how privacy.resistFingerprinting works, I see it apparently blocks access to a hidden <canvas> element on the page. We’re using a hidden <canvas> element to resize the images before we upload them to get automated suggestions, so if that doesn’t work, I’m guessing it ends up sending no data, or like a 1-pixel image or something, leading to the screwy results.
In addition to the remedies listed above, if you have resistFingerprinting enabled, you should see an image icon appear in the address bar of a page that’s trying to access canvas data like this:
If you allow iNat to use your HTML5 canvas data, automated suggestions should work normally again. What remains unclear to me is how we might detect that access to the canvas has been disabled like this. I kind of wish Firefox would simply raise an exception we could catch instead of silently returning data that apparently can’t be used for fingerprinting.