I probably shouldn't read the forum when I'm tired, but I don't think I understand what you're asking.
If your Alpine X100 is not compatible with Rockbox, then you need to boot into the original Apple firmware (turn the iPod on and immediately engage the Hold switch). In this case, Media Monkey will have placed your album art correctly and it should display under the Apple firmware.
If you want the Media Monkey artwork to display in Rockbox, you will need to make a second copy of each cover in your .rockbox\albumart folder with each album cover .jpg named artist-albumtitle.jpg.
So if you're playing Queen's "Night at the Opera" album (and your iPod shows up as drive letter "x"), your art .jpg for that album will be:
x:\.rockbox\albumart\Queen-Night at the Opera.jpg
Um...right? I'd suggest if you're putting all your art in one folder to specify the artist name like that, just in case you have the "Greatest Hits" from several different artists.
If you spell anything differently ("Night At The Opera" vs. "Night at the Opera"), Rockbox may not display the art correctly.
Lastly, check the bottom of this page:
http://download.rockbox.org/daily/manual/rockbox-ipodvideo/rockbox-buildap3.html#x18-355000C...for some limitations on how your .jpg files are saved and which symbols may be replaced.
Someone yell if I'm wrong--I'm tired and I personally use the "cover.jpg" image in each album folder for my album art.
Bedtime.