I personally prefer a text description of a character to an image, but I know that most don't feel that way. Here is a list of what I suggest (Should I make a guide for this? I see a lot of questions about it.)
1. Use a text descriptions: Absolutely no chance of getting in trouble.
2. Use a picture you drew or a photograph you took: (Never use a photo of yourself. Pets are fine though.

) A small chance of getting accused of art theft, but most likely not.
2. Color a free for use off site lineart from someplace like DA: Chances of misreading and using something not allowed or not linking to lineart and getting in trouble.
3. Use a doll maker like
www.dolldivine.com which has a bunch of customization games like MLP, wolves, dragons, horses, big cats, and lots of type of humans. The games range on how much you can customize them, but they're still awesome. Just remember to put that you use a Doll Divine creator and you're golden. That's all the credit you have to give. (If you use a different site just remember to credit the artist.)