I wasn't sure if people knew this or not or you cant actualy save them. But I think i found a way people could steal textures, I'm not sure though. Here's how i think it works
view someones account, go to there active inventory, there you can view there textures, and if i click there head texture it shows the image, and i think allows me to save it. Just thought id say something in case you can save it, I haven't tried, just wanted to report this in case it does work
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and it does, tried it on my own texture

Well, this is stealing then, and people can report it, you aren't able to use someone's textures, you should buy/make one for yourself.
You should remove that texture now.
And if you meant to tell us(all of us) that we can steal textures and it does work, its easy to report too.

That is how people can steal textures, yes. Stealing textures is not allowed, and can be a ban-able offence.