You can upload only image files to Photo Album. Supported file types are .JPG, .BMP, .GIF. You will receive an error message when attempting to upload any other file type. Renaming any other file type with one of these extensions will result in an error. You may also receive an error message if the photos you attempt to upload cause you to exceed your account's allotted bandwidth.
Another cause is trying to upload an image that has the same name as another photo you have uploaded previously.