Continued from this discussion:
http://universesandbox.com/forum/index.php/topic,749.0.html
* drumroll *
DUN DUN DUN DUNNNN...!
How to:
1: Go to Pictures/Documents/etc. then change the top bar with "C:/Program Files (86x)"
2. Go to the Universe Sandbox folder
3. Go to the Media folder
4. Find a galaxy you want to change
5. Click on a picture you want the galaxy to be, then put it on the media folder. Remember to rename the one you changed, so it won't be lost!
6. Run US1/2, it should work.