Going along the lines of what TwentyGotoTen has said, I would:
- Structure your images in the Media Library within folders (if you haven't already done so)
- Create a sublayout/xsl rendering that contains a repeater to render the images
- Add the control to the layout and set the DataSource of that control to the Media Folder
- The code should then retrieve all child items from that folder and render as necessary.
You may need the use of the Sublayout Parameter Helper to access the datasource from ascx codebehind.