Why can't I select any photo as my profile image?
If you use Flickr, Picasa, Twitter or Facebook you can use your profile image from these accounts - they will appear in the profile image list automatically. Photobucket unfortunately doesn't have the concept of a "profile picture" so we can't link to a profile suitable pic from this option.
Due to the fact that we need a specified width and height (and it needs to be very small in download size) we can't allow for any photo to be used as a profile pic. Gravatar does the resizing and cropping feature very nicely and it can also be used on other sites so we provide this as an additional option if you don't use flickr, picasa or twitter.