Here's some steps on how to locate and delete your photos:
1. Click on Account in the upper right corner of the screen.
2. Click on Profile.
3. Click on Photos at the top of the screen.
4. Locate the photo you'd like to delete.
5. Check the box under the photo. You can do this with multiple photos.
6. Click Delete in the lower right corner.
Note: Photos do need to be uploaded before you're able to delete them. Uploading photos costs 10 Coins each.