[ Thanks to Chris7mas for this link.
]
“This article overviews five image viewers available
for Ubuntu and also includes at the end a list of another five ones
which either are no longer maintained or are based on older
libraries (KDE3 for example).“Gwenview
“In my opinion this is probably the best image viewer available
at the moment. Built for KDE4, Gwenview comes with support for
virtually all image formats out there, tools to do basic editing,
tree-like file browser, support for tags, thumbnail previews,
cropping, image rating system, slideshow, fullscreen mode, support
for plugins and two view modes (Browse and View).”