Looks like it will be fine but they did not use standard colors for the wires.
So use the sticker labels on your old wires and make sure you put the green wire to Y and Orange wire to C.
But it is strange there is no G connection on your old T-stat because that is the fan blower control wire.
This is a Heat and A/C system correct?
Also you do not put a jumper wire on the Nest so when you connect R only use one connection to the Nest never put a jumper like they did on the old T-stat. The Nest will internally jumper power to Rh and Rc when you tell it the correct information about the type of system you have.
Houptee -- NJ Master HVAC Licensed Contractor
