I would like to suggest
imgbox (
http://imgbox.com) as addition to the list of recommended image hosts. It is operated by the same team as ImageBam.
Allowed file types: jpg, gif, png
Allowed file size: 10MB
Storage time: unlimited
Storage space: unlimited
Bandwidth: unlimited
Data safety: redundant storage over multiple servers, two data-centers
Speed: global content delivery system
Registration: optional - registered users get a great interface to organize images / galleries
Thumbnails: multiple sizes available (between 100x100 and 350x350 pixel)
Hotlinking: allowed