My opinion:
Imagine
+ Large number of supported formats
+ Convertion to large number of formats
+ Support for animations (viewing, extracting frames, converting to avi)
+ Very quick !!!
+ Possiblity of manipulating (Flipping, nagative, editing of palette, rotating)
+ Possiblity of setting image as wallpaper
+ Plugin support
- No EXIF information
(already has it
)
- No Full Screen option
(already has it
)
- No zoom option
(already has it
)
+ Multilingual / Translatable (as Clo noticed

)
ImageLister
+ Additional toolbar
+ Zoom
- Very slow,
- Small number of functions
SGViewer
+ Possiblity of manipulating (Flipping, nagative, editing of palette, rotating)
+ Nice Toolbar
+ Resize option
+ Full Screen option
+ Slideshow
+ Zoom
+ EXIF information
- Slower than Imagine
- No animation support
- No .ico support
So I choose
Imagine and wait for some improvements when
nyam will be back
