http://www.funpic.org/
Only sites in English and there are some countries that are not accepted, but:
- unlimited space (filesize limit of 1 MB)
- php & mysql (max 3 mb usage of mysql database but if you have a forum it's more)
- 3 GB data transfer
- no ads
I've got 2 sites there and they work perfect and fast.
http://www.funpic.de/ is the german variant and they give 1 GB space.