In the folder you have Art Tool installed, there should be a file called sample.tas. Open this in notepad, and change the file names around to [yourteamgoeshere].bmp instead of the usual. Then, in art tool, go to edit > load team art.
If you're using Ralph's 2001 set and all the team arts by Stephan Seguin, then the Menu Arts are all different and rather wrong. I've modified them to look like this:
[ArtTool]
TASVersion=1
[TeamArt]
Team1=Ferrari 2002.bmp
Team2=McLaren 2002.bmp
Team3=Williams 2002.bmp
Team4=Renault 2002.bmp
Team5=BAR 2002.bmp
Team6=Jordan 2002.bmp
Team7=Arrows 2002.bmp
Team8=Sauber 2002.bmp
Team9=Jaguar 2002.bmp
Team10=Minardi 2002.bmp
Team11=Toyota 2002.bmp
They aren't in correct 2002 order, they are in 2001 order, but with updated team art.
Hope you understand all that!