Yes, do avoid taking copyrighted images, please. Google Image Search doesn't really warn you about that sort of thing. Perhaps you should search on deviantArt for an artist and ask for a commission? You could also look up the artistic community on Tumblr, say in the starship tag, and ask for a commission or just for help/art donations. You could even become a fanartist yourself and give credit to the owners of the materials you use for inspiration and to measure against.