Currently there is only 2 pictures allowed on patron card. This is acceptable, however it would be nice to be able to add more with an "add another image" button or something along those lines. At the very least, could we free up a custom image by making the patron image a separate component? I've tried adding extra images to the XML code in the database, and it seems to work just by incrementing the image number value.
This is an excellent idea and could be easily implemented by modifying the code to allow the user to add more image fields in the interface. The back-end code which process the xml can handle it already as you have discovered. Also note that it is not necessary to include a patron image if you do not want to. In its current form the tool allows for any two images both of which may be other than the patron image.
Still valid.
Just a note that a good way to resolve the problem is to make a background image the size of the card with transparent background and place all images on it.