467246 Photos 100x - Add border + Fit to 51x71cm

I have about 100 images that need editing. The will be eventually printed out onto 50x70cm canvas frame. So, they all need a small ~1-2cm white border around the edges. If the image aspec ratio is for example 1:1.3, I want you to add an appropriate sized border so that it is centered/the canvas size will be 51x71cm with the border included. Knowledge of GIMP/Photoshop required. We need the quality of the images to be kept the SAME! DO NOT BID IF YOU CAN ONLY USE PAINT. This is a simple/straightforward job, I do not have the time to spare. I will be away for the next four hours, will pick a bid when I return. I need this job to be completed immediatley. If you can not get it done in a few hours, please do not bid. Thanks,