I think I understand what you mean, Birdseye. I, for example, don't have a camera I can download pictures with, and therefore use other pictures of the birds I've seen. However, I do copyright all of the photos in my gallery. Example:
The Red-Headed Woodpecker picture in my gallery has a description that reads:
This is one of my favorite birds. Beautiful red cap and contrast.
(C) ucb411 (Flickr) 2007
I think putting a good picture in your gallery makes it easier to identify a bird in question. All the time, posts say "see my gallery." Unless the pictures are of very good quality, they can be misleading. Therefore, I think it is appropriate and OK to use, only if copyrighted and respected, pictures that are not your own. Otherwise, I don't know of any rules against this.
Yours in birding,
ZBirdNerd
Year List (since 5/21):
Total: 90
This Week: Eastern Meadowlark, Cockatiel Parakeet, Northern Mockingbird, Snow Goose, Northern Rough-Winged Swallow
Favorites: Red-Headed Woodpecker, Eastern Phoebe, Black-Crowned Night-Heron