[Sebastian]

you need to make a directory on the server with a different path to the images for each style.

1) Make a directory in the forum root called "themes" example:

/forum/themes

2) inside that themes directory make other directories for each theme, example:

forum/themes/red
forum/themes/green
forum/themes/blue

etc... and upload all the images to each style its own directory, red, green, blue, etc..

3) go in admin cp, under Style click Download/Upload. under Upload existing style set select the style you want to add. below it Under Overwrite existing style make sure No, create a new style is selected. Click upload.. do this for all your styles.

4) still in admin cp under Style select Modify for each style you see select [fonts/colors/etc] under [image paths] make sure each of the styles point to the correct directory, example, if I have a style called "blue" your paths should look like this:

Image folder path: /themes/blue
Title image path: themes/blue/vBulletin_logo.gif
Reply image path: themes/blue/reply.gif
New thread image path: themes/blue/newthread.gif
Closed thread image path: themes/blue/threadclosed.gif

do that for each of your styles and everything should be fine when switching styles... hope this helps.