Option 1: Royalty Free & Free Stock Images
Okay, so you don't want to part with too much cash, if at all, right? We get it...money trees went extinct a long time ago anyways. There's truckloads of websites out there that have both Royalty Free images at low cost to consumers and if you search for them, you may even find some real sweet freebies! Some artwork is free for commercial use, so look out for the fine print...it could help you!
With these images and the help of some photo editing software like Photoshop, you'll be able to create a high definition masterpiece. Just pay mind to the restrictions (if any) associated with the image you're looking at before using it.
Here's a sweet list provided by Inc.com to get you started on your hunt for the best suited images to help paint the picture in your head.