Translator offers powerful image viewing, processing and conversion.

Features :

    Can read the following image formats : AIM, BMP, CadSoft, Clear, Degas, Draw, GIF, IFF, ImageIO, IMG, Irlam, JPEG, MacPaint, MTV, PBMPlus, PCX, Pineapple, PNG, QRT, Sprite, and TIFF.
    Can write the following image formats : BMP, Clear, GIF, ImageIO, JPEG, PBMPlus, PNG, Sprite and TIFF. Colour reduction (if needed) is performed using high quality Heckbert quantization and Floyd-Steinberg dithering algorithms.
    Can perform a variety of processing functions : mirror horizontal or vertical, rotate +90, -90, 180 degrees, scale up or down by an arbitrary fraction (performed by high quality algorithms), crop, filter (e.g. blur, sharpen, noise, custom kernels), bit mask, black and gamma correction, conversion to grey, range expansion, equalization, invert. Processing functions are performed on either the whole image (all functions) or on any rectangular selection of the image (all functions except scale and rotate).
    Can load multiple images, limited only by disc space (when memory is exhausted, your harddisc is automatically used for storage).
    Can perform batch processing 'by example' (simply load, process any way you like, save one image, then click 'Do others'). 

Translator is part of the Shareware combo consisting of Translator and Creator, which costs 15 Euro. As long as you're not registered, it will regularly 'nag' at you, but is otherwise fully functional.