I stumbled upoin free orion and i found since it is a free project the art ist under a cc license so we can use it.

For more about the license see the file in the zip.

I uploadet it as a bundle and again seperated by art type. 

The attribution is not madatory since the authors did not specify it:

The Art is from 

www.freeorion.org

Bundle.zip contains all files

 The Is this your own work? button does not seem to work please fix it.