This is a very simple job, that I can even teach you 1 to 1 how to do this yourself in future to avoid having to pay a fee for. I will teach you the full basics of photoshop, or any other image editing software to be able to do the basic things you will need doing for your website.
What you are requesting on it's own will take someone 5 minutes of their time, let me help you by spending an hour or more of my time with you, to teach you the basics of image editing software, and allow you to do this, and much more in the future by yourself with ease.