So, for example, one could make a page "all_images" and have a report (or pmap, which is simpler) like so:
+ \[[!pmap pages="*.png or *.jpg or *.jpeg or *.gif or *.ico"]]
+
+And then later, somewhere else
+
+ \[[!report template="images.tmpl" trail="all_images" pages="album/*"]]
+
+and that would show all the images under "album".