It looks a bit strange where the head meets the throuth, the head is darker than the throuth and it makes me feel the shading is wrong? Otherwise I love the design, very well done!
It depends how realistic you want it to be, of course, but a frog's thighs are mighty meaty compared with its shins -- and its feet, although large, are more delicate than you have drawn yours. Just a thought...
You can't have everything. Where would you put it?