Is it possible to write a plugin to add more info in Finder's Preview Pane? I would like to display the DPI and color mode (RGB/CMYK) for JPEG images, is it possible to write a plugin to add more info in Finder's Preview Pane?

Is there an API for developers to do so?
Probably more trouble than you want but if you open jpeg in preview and under tools menu click on 'Show Inspector' a window appears with image size, DPI, color mode (RGB) and other info. If that is too much trouble maybe you can look to see how Preview gets and displays this info.