The trick with Lithophanes is to work from the bottom up-
Basicly, the white parts of the image are the thinnest parts and need to be under a millimeter thick; 0.8mm is what worked here. The darkest parts are 2.75 mm thick.
Starting with an image that has a good range of contrast will appear most like a photograph, like this image of Mike Conley.
After downloading the picture, I did adjust it by increasing the contrast, so that the lightest parts where actually white, and the dark parts; pants and hair for example, where actually dark.
I used MeshCAM PRO to generate the height map, setting “black” to Z+ and leaving the Z height dimension at .1" which is roughly 2.75mm
The corian stock i had on hand was 6mm thick, so I defined my stock accordingly and since I knew the white part of my image was at the bottom, I added .8mm to the bottom of my stock.
I roughed with a 1/8th ball, and finished with a 1/16 ball with a 25% step over.