what if: alt-text, but it's embedded into jpegs' and pngs' attributes so that saving a picture and posting it somewhere else also copies the alt-text

· · Mastodon Twitter Crossposter · 13 · 22 · 46

@devurandom Huh! You know, it looks like EXIF has an Image Description field...I wonder what the limitations on it are, and if anything uses it like that? I may have to do some experimenting

@devurandom This is a rad idea and seems so simple, and yet I had never even thought about it!

@devurandom doesn't PNG have an internal mechanism for extensions which is why APNG can display something even if it's not animated

@devurandom would not recommend... Alt Text could include a bios

@devurandom yes! But a lot of platforms (correctly) strip EXIF data because that can inadvertently expose personal info like location. You'd need to signal that you actually want it included

@devurandom looks like that's always been part of exif

0x010e ImageDescription

(I'm sure I've seen someone else post about this but can't remember who!)

@devurandom There already is an 'ImageDescription' EXIF tag that could be used for this, just the software needs to account for it.


It would be quiet difficult to implementiert such a feature in a way that makes sure that no information leaks that the person uploading didn't really want to publish.

@chrichri @devurandom On upload, extract the attribute and suggest to the uploader as alt text. On submission of post, add alt text to exif attribute.

@clacke @devurandom

Yes, this sounds simple, but is it really?

E.g. my workflow is to delete all exif tags from pictures before uploading them and I'd recoment this strongly to anybody wanting to prevent information leakage.

The software used for this would have to change to give the user the option to leave the comment field untouched.

Or you'd nuge users into a less secure workflow by making them rely on code provided by the services you upload to that is supposed to remove other tags.

@devurandom Isn't there [comment] metadata for image formats already?

@devurandom what if: database of image hashes with accepted alt text so common images like reactions and memes can have good alt text automatically

@devurandom The PNG format already supports this through the addition of a tEXt chunk with a keyword of "Description". Unfortunately, the PNG specification also mandates that the text must be encoded as ISO-8859-1 instead of UTF-8.

@devurandom It's basically like watermarking where you got the image from, it's dangerous for privacy

Sign in to participate in the conversation

cybrespace: the social hub of the information superhighway jack in to the mastodon fediverse today and surf the dataflow through our cybrepunk, slightly glitchy web portal support us on patreon or liberapay!