There is a modified version of the Adds Images as planesImport Images as Planes add-on that lets you stack series of images on a determined axis and determine the offset.
The script can be found HERE
The full thread on blenderartists.org
NOTE: Keep in mind that is a modified version of the original script so you might need to move the original out of the scripts folder so that blender doesn't complaint of having multiple addonsadd-ons with the same name.