Have you tried googling "My Little Pony G2 Coloring Pages"? Then click on the images tab and scroll through until you find what you're looking for. Unfortunately, you'll have to sift through all the generations but I've found if you only search "My Little Pony G2" all that comes up are the actual toys. I don't know if those would be high resolution enough for your needs, but it doesn't hurt to look.
Googling "My Little Pony G2 Artwork" also brings up pictures of what you want, but also some of the toys.