For the dog (don't ask how I did Lena; lol), I first used G'MIC's Isophots and which gives the liney effect. I used that as a selection for stroking with GIMP's own Vine Brush. I kept the liney, colorized it some, and used them as the Vine bark. I used an illustration technique that I developed to enhance the Vine part more (Dup, G'MIC's Bilateral Filter and set the layer to Grain Extract, merge Down and set to Grain Merge and duplicate to taste). Then I merged the Vine with the bark. I created a brick wall fill (one of many textures that I have) and then dupped the Vine/bark layer and ran Motion blur at 235° and set that layer to burn. Might have done some additional enhancements, but the outline above will get you the gist of the work. Glad you like the result tstandiford.
