Scratch

Many of the sprites on this website are copied from other places.  Just because someone else copied them first does not give you any rights to copy the artwork.  To be completely clean about it, you should track down where the artwork originated, and ask permission of the copyright holder.

Many of the sprites came from sources that do allow fairly free use of the artwork, though, so if you can find the source, you can often find that you do have permission to use it.

Suggestions:
    1) if you create your own artwork for a project, mention this in the notes, and tell people whether they are free to use your artwork for other purposes, or whether you are retaining your copyright. 

    2) if you copy artwork from another site, give the URL for the originating site in your project notes, so that someone else can get the artwork themselves, or ask the originator for permission to use the art for another purpose.