Look on ELSI for Visual Q. It is quite a nice gui graphics editor. It allows selecting a range and clipping (cropping) to that range, adjusting brightness, contrast, gamma, rotating, mirroring, resizing, quite a few nice filters, like blur, sharpen, mosaic, swirl, and emboss. And it supports jpeg, png, bmp, tiff, and some other file formats. It also has a "batch" selection on the file menu, which I presume allows batch processing of some sort. I just found it last night, so I don't know the program extremely well. But I sure like what I see.
It works on the sl-6000 in portrait or landscape. The japenese author of the program has made a nice effort at translating his webpage and the software.