In the meantime I am using TinyPic, which has been bought by PhotoBucket.
However I am going to be completely moving to DropBox soon as it makes synchronizing all my files between my computers extremely easy, secure and offers versioning of files and a gallery functionality too. (and more)
All of DropBox's features can be read in the Help Section on the Dropbox homepage, so let me simply say I think it's a great solution with lots of potential.
If anybody here plans to be using Dropbox too, you can send me a PM here on the forums, so I can PM you my referral link which grants us both a free 250 Mb increase of storage space.
I do not want to simply post my referral link as I do not plan to spam this option and I leave the choice completely up to you. (if you are doubtful about this, you can read into the details in the FAQ section about Referrals on the DropBox homepage)