For background, this post on db zero provides background on what is going on.

Lemmy.world had to shutdown a community and temporary restrict signups, other instances have purged image caches, and dbzer0 is using a scanner to prevent images from being uploaded if the get flagged.

  • u/lukmly013 (lemmy.sdf.org)
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    10 months ago

    Just a note: The images themselves don’t get federated, just the links to them (except thumbnails on posts). So the content is only on the instance it originates from. This at least makes the issue slightly better as hosting the images would be far worse.
    Edit: Oh no, it seems the full resolution images are (at least sometimes) indeed getting cached.

    Theoretically they can actually be federated when encoded as data: URI, but thankfully there’s a limit of 10k characters which is basically nothing when you want to put image into it.
    Example:

    • nickwitha_k (he/him)
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      710 months ago

      I haven’t looked into the code yet but, I was given the understanding that Lemmy also implements a local pull-through cache for images in order to try to improve performance. So, if a user on our instance came upon CSAM or other illegal images while browsing through SDF, a local copy may be cached.

      • u/lukmly013 (lemmy.sdf.org)
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        710 months ago

        Oh, crap! You’re right. I just stumbled upon a post with image on i.redd.it. At first it didn’t load, as expected since I blocked *.redd.it domain, but then after a while it did. I checked the image URL, and indeed it’s coming through lemmy.sdf.org. And this time it’s the full resolution image. Maybe it wouldn’t be a bad idea to disable that if it’s possible.