Fotoxx
Fotoxx is a free open source Linux program for image editing and collection management
XnView MP
XnView MP – free and cross-platform, versatile and powerful software for viewing, organizing, and editing photos
RPhoto
RPhoto is a lightweight free and open source software for easy photo handling on Linux and Windows
Avvie
Avvie – free and open source software for quick cropping and downsizing images
Converseen
Converseen – free and open source multiplatform batch image converter and resizer