Irfanview (excellent image tool)

[NicolaM]

In case you haven't come across this excellent freeware :
http://www.irfanview.com/
Used for viewing/converting images. It also works with lots of file types.
Also very fast, compared to the image software that comes pre installed on Windows.

 

[ClubMan]

Just to clarify - freeware for non commercial use. This tool is mentioned here along with some other alternatives:

[broken link removed]