Original source is allowed and preferred over the approved hosts. If your submission is not on the list of approved hosts, but it is an original source, please use the tag [OS] so your submission is not removed in error. If your image is rehosted from another approved host it will be removed.
If you took the photo yourself, you can signify this by using the tag [OC] (original content). If you are a photographer who submits their original photographs here, please message the mods to receive some special flair.