How to change a photograph to look more like a drawing

[rich2005]

First: The image you posted is in color indexed mode. This limits your image to 256 (maximum, can be less) pre-defined colors. Probably comes from the background image. Convert images to RGB mode Image -> Mode -> RGB

Then: Asking a question like yours, post your image as a Gimp .xcf with layers (saves us poor folks having to separate your image)

You could try applying a curve Colors -> Curves