Are you looking for a way to read out the metadata of the images? I've had good success reading the metadata out with PHP using the GD Image Library resizing function. This doesn't take the library as the input, but rather strips the metadata from the actual files - maybe this would be an option? I use in my website's internal programming to resize images and load metadata into searchable MySQL tables used in the programming of the site.
Let me know if you need help in figuring this.
Raymond Klass Photography and Workshops