Scriptable Java app for scientific image processing
ImageJ is a Java based application for analyzing images.
ImageJ runs either as an online applet or as a downloadable application which you'll find here. ImageJ can display, edit, analyze, process, save and print 8-bit, 16-bit and 32-bit images and supports most major formats including TIFF, GIF, JPEG, BMP, DICOM, FITS and "raw".
The main use of ImageJ is that it can calculate area and pixel values which may be useful for graphic designers. It does however go a little beyond that too, allowing you to measure distances and angles, create density histograms and also line profile plots. It supports other standard image processing functions too such as contrast manipulation, sharpening, smoothing, edge detection and median filtering.
Although ImageJ can be a bit slow in Java, its a decent image analysis tool considering its completely free.