A 5770 should be fine, you won't really need anything else so long as it's photo editing.
Thanks verymuch for your reply. Actually the Dell Inspiron 580 would be with a ATI Radeon™ HD 5450 1GB DDR3 graphics and if I got the Dell Studio XPS 8100 it would have either AATI Radeon™ HD 5770 DDR3 or an Single 1.8GB Nvidia GeForce GTX 260 for an extra 50€. I tend to always go overboard (given that I am not a techie I tend to think bigger, more expensive is best). Really appreciate your help. thanks, Jayne