Not working for me at all, with my photos or with the samples provided by the site
I always get a variation of the same thing:
The image shows a pattern of alternating dark green and light green vertical stripes. There is no discernible background or foreground beyond the repeating pattern itself; it's an abstract design. There are no objects or spatial depth present in the image.
The image does not depict any people, emotions, racial characteristics, ethnicity, age, economic status, or lifestyle. There are no activities taking place.
There is a privacy setting in firefox that causes this for me on most websites that require photo upload, not all sites, but consistently the same sites.
Ebay for instance, most reverse image searches etc.
in about:config - > privacy.resistFingerprinting
It might not be that setting specifically, but turning that setting to "false" does fix this for me.
There might be a more granular setting that does the same job but i don't know of it.
Not that i'm recommending turning that off, that's your call.
There are eleven settings that start with "privacy.resistFingerprinting". The first one, which only says "privacy.resistFingerprinting" is set to False by default and I still get the colored vertical lines.