Well, I thought I would do a little summary of my process for doing the lions. It is based of course on the technique that Ruth McDowell details in many of her books. I do things a bit differently though as probably anybody does when they have worked with someone else's process.
I first find a photo I really like and this is really important. I try to find a photo that has a good range of values in it. I then use Photoshop (or any photo program) to change the photo to black and white (desaturate the color). I then "posterize" it so that there are larger areas of one shading. I again check the picture to make sure there is enough differentiation of the areas and that it hasn't gone to far to "cartoon" like. Next I take the black and white image to Staples and have them blow it up to double size. I use this as my base. I use transparent plastic to trace around the different clumps of shading, getting as much detail differentiation as I can. I then put a piece of tracing paper over this and start deconstructing the drawing by trying to find large linear components. After I have sub-divided the drawing using these large linear elements, I just keep subdividing until you can begin to see the original image in this large straight line piece. I have used curves in one piece as well but do prefer the more abstract representations created with the straight lines.
This is the posterized version of the converted picture.
After I have gotten the tracing to where I am comfortable, I then take a picture of the tracing paper drawing. I determine how large I want to make the final piece at this point and use an online poster program to blow up the tracing paper image into the size I want. The lions took 49 pieces of paper (4 1/2 feet by 6 feet). If the final piece will be less that 3 feet by 4 feet, I will have Staples again blow up the image on their large copier and will make two copies (instead of using the poster program).
I then use use a colored marker over the solid black lines to differentiate the sections. Now it is important to make sure all the lines on this original drawing are dark enough. Then I place a piece (usually have to tape a number of sections of freezer paper together) of freezer paper over the whole drawing with the shiny side facing up. I carefully tape it to the blownup drawing and then tracing using a thin black permanent marker all the lines onto the freezer paper. This will be my pattern. I then turn the freezer paper over and make all the tick marks so that I can put the pieces back together (see Ruth's books for her techniques here which I use religiously).
This is a closeup of the mane on the male lion.