PhotoFiltre 6.1.5 - Almost Portable and Free

http://www.photofiltre.com/
On this site you can find PhotoFiltre 6.1.5 - a nice little photo editor with viewer.
It is free and works from USB (its size is less than 3MB). You only need to copy PhotoFiltre.exe and TranslationEN.plg (if you want English instead of French language) from the folder with installation.
It seems to me that PhotoFiltre 6.1.5 may be good portable image editor and viewer.