Photoshopping images for a website

I need to put a series of portrait shots on a new website. The original portraits have been supplied by different individuals and are taken against a range of different backgrounds. I need them all to have a uniform appearance - e.g. against a grey background with a gradient. Some may also need sharpening. Example of the ideal end result attached below, with an example of what our raw material is. Up to eight images will be supplied for editing.