I'm going through and cleaning up duplicates in my collection, and I'm getting a decent amount of duplicates from e621 that are pixel-for-pixel identical images, just stored as a PNG instead of JPG, so the filesize is just 5x bigger for no reason. I don't know why they're doing this, exactly. My best bet is for the massive filesize boost + the thought that a PNG is better inherently?
So I suppose why I'm posting here is that I'm unsure what to do. In the past, I've simply uploaded the original JPG and flagged the PNG re-encode. However, I've recently come across an account with over 400 approved uploads, most of which are these PNG-ified JPEGs.
They are also literally the only person uploading art from one particular artist (there's 5 images from other uploaders, and 100% of the user's uploads are for that artist. so they make up 98.8% of the artist's uploads). So replacing all of these uploads would effectively ban them from uploading ever again (understandable, but upsetting given how much work they've put into the site, and seemingly care? I had this happen to me before. Tumblr had the highest quality at the time, years later uploads were made that were higher quality, I suddenly had a negative base upload score.)
There's also the fact of just I really don't want to manually upload 400 images just to end up with images that are visually identical, and only offer the benefits of being much smaller, and having true ICC profiles.
So I guess I'm kinda looking for advice on how to approach this. Ideally, I'd like just a slap-on-the-wrist of the users that are genuinely trying and just misguided, and continuing to allow them to upload. But I think it would also be best to somehow mass-replace their uploads with the JPG versions that they effectively are.