A quick study of molding profiles
What makes a good profile for a frame? That question really depends on how gaudy you want your frame to look. In looking into this, (A)I created a script in openscad that will take an SVG and convert it to a frame; you can specify how many sides the frame has, 4, 8, or 180 if you want a circular frame, and it'll take your SVG shape and rotate it around the circle.
Profiles are abound on the internet, this site has an SVG download of many different profiles you can play with. I tried to get fancy by using a skull outline, but it really didn't look like much:
In the end, I was framing a goose, so I took the outline of the goose foot, and used that as the profile for the molding:
Initially I was doing this in Blender, but it was kind of a hassle, and the openscad workflow is much quicker and reproducible.