I know there aren't many, but they're hard to find because a lot have large watermarks in the middle or characters on them. Also, some are from actual anime/from artists who haven't given permission to use them... Are we going to worry about that? If so, I can remove those from the album.
As for permissions these things are on the internet and we aren't selling the game so even if someone claims/even finds the game and wants us to remove their background in the end I don't believe they have any actual power. Not that we'd not remove it to spite them, just saying.
I would highly suggest you guys re-examine the copyright laws and fair use, especially for visual artworks.
1) Just because you found an image on the internet does
NOT make it public domain. The internet in considered a tool to access information and services. You have to be absolutely sure that the copyright holder has made the image "public domain". If not, then you must ask for permission to use their artwork, except for a few exceptions.
2) Even though you are not selling the game, this does not mean you're avoiding copyright infringement. For example, let's say you draw a character and posted the drawing on the internet. Someone comes across to your picture and decides to use it for an advertisement and is not making money directly from your work. Unless you had given the permission to that person, that person has infringed your copyright.
3) Fair use leans more towards non-commercial educational purpose than personal use. It's considered "fair use" under the non-commercial educational purpose when you're constructing a game and learning how to code and imputing sounds and images. That is considered "fair use". However, once your game is shared publicly (say via internet), then it's no longer considered educational purpose. If you don't have the permission from the artists to use their artwork, then it's considered that you have infringed on their copyright.
I just don't want to see all your guys' hard work to be interrupted and discontinued because of a mistake
.