For those not familiar, there are numerous messages containing images being repeatedly spammed to many Threadiverse users talking about a Polish girl named "Nicole". This has been ongoing for some time now.
Lemmy permits external inline image references to be embedded in messages. This means that if a unique image URL or set of image URLs are sent to each user, it's possible to log the IP addresses that fetch these images; by analyzing the log, one can determine the IP address that a user has.
In some earlier discussion, someone had claimed that local lemmy instances cache these on their local pict-rs instance and rewrite messages to reference the local image.
It does appear that there is a closed issue on the lemmy issue tracker referencing such a deanonymization attack:
https://github.com/LemmyNet/lemmy/issues/1036
I had not looked into these earlier, but it looks like such rewriting and caching intending to avoid this attack is not occurring, at least on my home instance. I hadn't looked until the most-recent message, but the image embedded here is indeed remote:
https://lemmy.doesnotexist.club/pictrs/image/323899d9-79dd-4670-8cf9-f6d008c37e79.png
I haven't stored and looked through a list of these, but as I recall, the user sending them is bouncing around different instances. They certainly are not using the same hostname for their lemmy instance as the pict-rs instance; this message was sent from nicole92 on lemmy.latinlok.com, though the image is hosted on lemmy.doesnotexist.club. I don't know whether they are moving around where the pict-rs instance is located from message to message. If not, it might be possible to block the pict-rs instance in your browser. That will only be a temporary fix, since I see no reason that they couldn't also be moving the hostname on the pict-rs instance.
Another mitigation would be to route one's client software or browser through a VPN.
I don't know if there are admins working on addressing the issue; I'd assume so, but I wanted to at least mention that there might be privacy implications to other users.
In any event, regardless of whether the "Nicole" spammer is aiming to deanonymize users, as things stand, it does appear that someone could do so.
My own take is that the best fix here on the lemmy-and-other-Threadiverse-software-side would be to disable inline images in messages. Someone who wants to reference an image can always link to an external image in a messages, and permit a user to click through. But if remote inline image references can be used, there's no great way to prevent a user's IP address from being exposed.
If anyone has other suggestions to mitigate this (maybe a Greasemonkey snippet to require a click to load inline images as a patch for the lemmy Web UI?), I'm all ears.
Most AI image generators that generate images add EXIF metadata indicating that the image is AI-generated. This helps people who want to identify AI-generated images readily.
In the case of ComfyUI, it even includes the entire workflow
like, another ComfyUI user can just grab the image, drop it onto their ComfyUI Web UI and they'll be right where the generating user was.
Unfortunately, because EXIF metadata can contain location information
some cameras and such add it
and this metadata led to people posting images at places like Reddit being doxxed after they didn't realize that they were posting their GPS location and maybe real name, stuff that some cameras attach. As a result, a number of image-hosting places simply strip all metadata, to prevent users from from accidentally leaking this information.
Pict-rs, the software package that Lemmy hosts run to permit image uploads, does this. Unfortunately, it means that those "this is an AI-generated image" tags get stripped off.
So, for example, on my system, with ComfyUI, using ImageMagick:
"Properties:prompt" has a JSON encoding of the workflow.
Sample images generated by various AI image generators are readily-available on civitai.com.
For this generator that generated this image on civitai, it looks like the parameter is "Properties:parameters".
I believe that there are a small number of such tags today.
It would be technically possible to just not have pict-rs strip that particular tag (or tags, if there are others?) off, have a list of "AI-generated tags", then have Lemmy add some visual indicator that an image is AI-generated. I'd suggest that this is probably a better longer-term route to indicate that an image is AI-generated than manually-tagging post titles, for a couple of reasons:
Spiders that index images on the Web will know that the image is AI-generated and can flag that for users and let them use that as a filtering criteria (e.g. Kagi Images permits for this). They aren't going to understand tags in post titles, but the metadata tags are somewhat universal.
Doesn't require manual effort if an image can have some indicator or flair or whatever put on it automatically. And I guarantee that some users are going to get this wrong just by accident, because different instances have different rules. Easier to change how a computer works than to change human behavior across-the-board.
Works on all instances.
The information remains attached to the image even if downloaded.
Works for images that aren't just the subject of single-image posts and don't have an associated title.
Speaking purely for myself, I kind of like the open-source, collaborative aspect of sharing the workflows or prompts, since it helps other users see how an image was created and learn from it; it's something that I'm glad to see the generators include, and I'm kind of sad that we strip it off on the Threadiverse.