Just a minor addendum...
There are a wide variety of sites for free image hosting. Some examples are:
http://www.2and2.net/ http://www.imagevenue.com/ http://allyoucanupload.webshots.com/
There's also a pile of others listed here:
http://www.free-webhosts.com/free-image-hosting.php
Some have file size and format limits, some do not.
Note though, that if you want to retain copyright to your images, make sure you read the small print on all of these sites!