Here's a short list which i've compiled for your easy reference... Below are links to website which provides free online pictures/images hosting.
A good practice is to read their 'TOS' (aka terms of service) and also the 'FAQ' (aka Frequently Asked Questions) before using their services.http://my.fotopic.net http://www.imageshack.ushttp://www.photobucket.comhttp://www.freeimagehosting.net/http://www.photoserver.us/http://www.piclynk.com/
Note: You may have to register for a free account in order to use their free services.
The list is not completed, just to name a few good websites. You may wish to add on if you have any recommendations too