Michael,
I don't have a picture to show you, but a Walther Model 7 looks just like a Model 4 except that the ejection port is on the right side!! Since it is a 7.65 cal, it also looks like a baby model 6 which was big and in 9mm cal. A good book for you to get would be "German Pistols and Revolvers 1871 to 1945 by Ian Hogg". There is a picture in there along with disassembly instructions.
Dave