Website Photo Editing

I need a photo editor who can resize and extend the backgrounds of my images for website use. The current size is 800*800 and the required size is 1100*1500. When they are resized, part of the product is cropped. So i want someone to extend the background as they crop so as to keep ample space product. The final edited photos should be in the same file format as the originals that are handed over to you.