VMVendor , varible / string for vendor image

[3djunkies]

hope all is well sorry newbie first posting ...

I am using Vmvendor * essentially each user has there own shop" with virtuemart most things works but the user has a profile image which is controlled by the Virtuemart I cant find the string that controls the image upload size , it say image size is too big , where is this located I need users to be able to upload a banner for there shop using the VMvendor profile avatar that calls it .

cheers