It actually depends on what file type does your online services accepts. For e.g. Flickr supports JPEGs, non-animated GIFs, PNGs and TIFFs. SmugMug, on the other hand, support JPEG, GIF, and PNG files but, it does not support TIFFs.
Here is the list of all supported file types for each service
PicBackMan is a free photo/video uploader that helps you to keep your memories backed up to your favorite online services.
Users in 130+ countries have backed up.
... an excellent job of uploading more then 300GB of photos to 2 different services