It isn't difficult. It is basically auto digitising. The trick for good results is choosing a suitable picture!

I agree, the quality of the picture is the important thing. I tried some old black-and-whites. They looked fine to me, but the software thought otherwise.

I believe it also depends on the software you are using.
I have done quite a few using Sfumato module in Embird, with varied results, and I found that the picture you use should preferably be a Larger size 8x10 with extremely good detail.

If you are using Embird they have a free tutorial you can download that might help you
https://www.embird.net/sw/embird/videos.htm

Scroll down the page until you see Sfumato Stitch, click to open and you will see four files to open.
It is fun to do but also frustrating and you might even have to manually digitise small details that don't turn out properly.
Hope this helps.
Hugs n roses, M

I think your PE software has a pretty good program for this...I agree with the others...good quality picture is the key...