I found this great site thanks to A Thoughtful Place. She has floral prints in her dining room and come to find out she made them herself off a site called Botanicus.org. My dining room has mirrors on one wall, but was lacking art work. I decided three of these prints would go great on a gallery wall. I went here and printed them on white card stock. It took playing around a bit until the print size was a full page.
When you get to the home page click on the orange download. Beware! It is 410 pages so it might take a bit. Then, just scroll to your heart's desire and print whichever ones will work in your space. You will need to choose your print size on page setup.
After I printed them I purchased 2 gold frames that I found for $8.99 at Michaels. Combined with a 40% off coupon, these frames are a steal! Here's how they turned out.