XnView Software

yes thanks for that.. however really the idea is to be able to quickly flip between different colour channels.

well as you said replaceing the .rgb for .sgi in the file requester does not work for batch processing which is what I need. You could have another file type but frankly it would be much simpler and probably more logical jsut to have the extension name an option in the filetype options menu...

at present xnview labels sgi images with the .rgb extension. I try to override this by specifying .sgi in the output filename (when doing sequence or multi convert) but xnview always creates files with .rgb as the extension.

Can it be included in the file format options, to use either .rgb or .sgi?

numeric number sorting would be VERY useful. I use a lot of unpadded images ie. the format test.1.jpg, test.2.jpg especially when moving from one image to the next using the mouse wheel which is a very nice feature, the images usually come in out of order.
Maybe there could be an option to 'always ...