[quote=@Techspert]
<Snipped quote by Armed Forces>

This can probably be considered transformative. But unless the image itself is the art (as opposed to being a piece of a larger project considered the "artwork"), it's fair for you to use. If you're just printing a picture someone is selling, then that would be in violation of copyright law.
e.g. If someone is selling portraits or photos, you can't. If someone took a picture of their bike and you want to use that bike image, it should be fine.
It's also possible that even if it is artwork, if they're giving it away, you should be able to use it. If they're selling it, this would still perhaps be considered transformative but would break the terms of use.
[/quote]

The images are the art being used on the sleeves, the only alteration is a bit of cropping to fit them. And the image source was on Pinterest when I found it.