I really don't need to make this post. This is more a fair warning than a genuine question, since the "question" I'm supposedly making this post for can be answered on google.
So I just imported a ton of my old windows folders into Hydrus, cause my HDD had like 10gb of space left, and I figured if I didn't start on it now, I'd eventually not have the space to move things into Hydrus.
I wasn't sure how to really do it, so I set a long unique namespace for each filename on import, specific to each folder. And I ran a batch rename command in irfanview (image-viewing program) to rename each image to its date order (I only used its number placement [e.g x/2560], not anything fancy like 2018-01-01 and the exact timestamp and all that). Imported the batch rename folder under its own namespace, too.
I thought I was doing pretty well for myself, since I knew I would never be arsed to sort windows folders ever again when I keep Hydrus open 24/7 (tbh I wish it could be minimized to system tray, though. Dunno if that's possible).
Well I was importing my last big folder, and I noticed a single ignored file. I saw a few of those but never paid them any mind, since I know I've saved imaged on mobile before, so like when you save a twitter image with the ":orig" extension, it doesn't save as an image. Or you save a manga page with an incorrect extension, Chrome mobile didn't correct its extension, so Irfanview will ask to if you open it on desktop. Basically I didn't think anything Hydrus ignored was actually usable.
But I checked it anyway this one time, for the first time, and it was usable; Hydrus just said it was a decompression bomb.
I don't know what that means, but I'm pretty bummed out I very likely lost usable images just because Hydrus flagged them as a decompression bomb.
I realize for my safety I shouldn't really have something like that on my HDD, where the right script can trigger it and compromise me, I don't know. But I'm assuming it's an embedded file before 4chan disabled them, cause I remember seeing a thread in the wild of running a script on your 4chan folder, and it exports any embedded files within into a different folder.
I don't really know what I'm saying. Sucks.
It's not like I even use reaction images anymore. Largely I only save porn.