There should be a drop down box. I was hoping this discussion would be more on the lines of what type of selection process one uses to pick out a frame plus mat etc. for a particular photo since I am color coordinated challenged. But you should be able to click the box and it gives you more options.
When I frist started out doing shows, I spent hours,trying to pick out a nice mat, that had the same color or complimented the image and then the frames! Now, I have a chunky black metal frame( I buy the parts and assemble them myself and a white mat, usually a double mat and that's it.
When I did the shows, people would ask if I could change the mat to another color, to match their sofa,walls,carpet and I know I lost sales because my choice of color, wasn't their choice!
So keep it simple and always offer the image, along as framed, as a print only and you'll increase your sales!
Some galleries will only allow white mats and black frames. And that combination will work in any home or office, never clashes with any existing color. Here's the place I get my frame, but check for pricing, it's been a few years since I bought a large order and back then, they would supply the mat, cut for free, with each frame ordered! Now, fre shipping over $40!