One thing that can come in handy when doing HTML generation is code to extract the dimensions and other properties of image files (preferrably without the overhead of unpacking the files' entire contents). libexif looks promising for this purpose ... though it seems the 0.5.9 version doesn't quite compile out of the box on Mac OS X. (If someone has a patch that will spare me the fun of delving into autoconf, I'd appreciate a holler.) The jhead CLI utility that EXIF Viewer wraps seems to work well and offers another possibility.