The concept was older Toph, grounded and in her element - not an action shot but just very relaxed and comfy - so almost a pinup style if you will, with her lying on earth/sand.
Enduro went a step further and included some earthbending into the composition that just feels so very Toph - it's almost like she's using her bending to get a view of something far into the distance.
Full view:
Close up detail:
+ artist's post on DeviantART if y'all would like to fave/comment there :D