how to shrink objects

im a total noob at this...got the program as of 10 min ago and im trying to figure out how to shrink things down...like rims...i have the rims completely trimed of all other crap..now i just want it to shrink...so i dont have a monster truck...lol...anywho if you can help thanks :screwy:

if u r using photoshop it edit>free transform

yea thanks...i should have just messed with it alittle longer...found it after i asked the question...thanks anyways