The rules are simple in my group:
1. Taken photos only.
2. Accepted only square photos.
3. Image quality should be high.
4. Images are not welcome in the style of "dirty treatment."
5. Images are not welcome in the style of "Family Album" and "I'm on a background ..."
6. The Administrator may reject your photo, if it does not meet the standards.
Typically the administrator looks at your gallery rejection of your request and looking for work in your gallery replacement.
Thank you for your understanding and good luck!