I often think of trying to make or alter existing php galleries ... I usually give up after a few pages of terrible hand coding (; I have, however, found a so far cool flash alternative:
http://www.airtightinteractive.com/simpleviewer/It took me about ten minutes to get this up and running:
http://luminescher.com/images/test/ (most of that time was dedicated to making thumbnails and resizing images).
What's good about it is that it's very basic and flash sometimes seems more exciting than it really is - it's also fairly simple to customise, and while it doesn't really keep count of the number of pictures in your gallery (except on the coding side of it - each picture has to be numbered in order), you could add that information to the caption, anyway.
What's "bad" about it is that you do have to make 45x45 thumbnails (or smaller, if you wish) and I had to resize all of the large images to around 500px in height. I imagine that can be fixed in the index.html file somewhere, though, but keeping it at those dimensions does prevent scrolling (I believe).