i can produce a heightmap using "Shape from shade" from the second image in the first post
-- i would need time to edit it first to remove the lettering and such
-- it looks like it would work "ok" , not perfect but fine

now i work in 32 bit float , but can convert it to almost any format

and a 8 bit heightmap WILL look stepped
( think of the stepped pyramid in Egypt )
8 bit images only have 256 tones of gray

16 bit heightmaps have 65538 tones of gray


being unpaid , this is a spare time project