I would probably approach it like this...
Add all your images to your visitor_add.htm template. Each images would have it's own radio button.
Then when user selects one, it will write the filename of the graphic they chose, into one of your user fields. Then the filename of the graphic they want to use would be entered automatically for them into the user field.
Then you can setup that userfield to display an image.
Like this:
Choose an image:
1. 2. 3. 4. 5.
When user selects #3, use javascript to write:
Your Image: image3.jpg into the user1 field textbox.
Now, you would have to do some php modifications inside the results_list.php and results_list_format.htm and results_details.php and results_details_format.htm templates to get the image to show properly. when only a filename is provided. You would have to hard code all the other html tags needed to display an image.
Something like this:
CODE
<img src="$user1" width="100" height="100">
Although we have never done this modification, I'm sure something like it or similar would work.
Hopefully, this will lead you in the right direction.