Cinderella Rabbit

It looks pretty good, though I do have a bit of CC, first here's a ref image of 'Jessica' It's actually Hedi Klum dressed as her, it came from google, I don't know why she's dressed as Jessica Rabbit either xD [link]
But she looks enough like her so alls well I suppose.
I couldn't find any good screen shots of her from the movie, you'd think they'd be easy to find but I guess not. >.>

Anyway I know how it is to have your pc freezing after every stroke T_T It doesn't do that so much with smaller pictures, you could also try making sure your computer has lots of free memory before starting on a huge picture.

Now~ Onto the critique, these will mostly be a short list-like one because as luck would have it, I have lots of work tomorrow xD And I know you don't want to change this picture anyway (I know I wouldn't after 20 hours O.o) so hopefully these will be more useful toward your next picture. But if you need any further crits or anything don't hesitate to ask

Coloring and Shading-

- White is rarely shaded with grays, it usually takes on the color around it, in this case, the shadows would be pale green.

- The light source is a little scattered, the dress and skin are shaded as if the light is coming from somewhere near the green wall, whereas her hair is shaded as if it's in the other direction.

- Try to avoid shading with just darker or lighter versions of your base color, if you look at clothes, trees, people etc. You'll see that shadows usually have a cool (as in cold, but they can be pretty cool sometimes xD ) hue about them such as blue or purple.

Background-
I really love backgrounds, though they are hard to draw, they really add alot of depth to your picture.

- The background doesn't even have to be very detailed, as long as it adds depth to the picture and doesn't make it look like a sticker. (unless that was your intention)

- Start with your base color, ex; blue for the sky.
Draw the farthest objects in a color just a little darker/more saturated than the base color and build your way up until you're at the foreground. *that's where the character usually is*


- Your background should interact with your character, especially in paintings/drawings such as these. (portraits, etc.)


Anatomy -

- Take a look at the Heidi Klum picture above, She's about seven or head head-lengths (measuring by the size of the person/character's head) tall without the heels. The legs here are about a head too short.

- The hip (as seen under the elbow) is too far out to line up properly with the legs.
- The leg that isn't bent should be farther back, and her foot pointed a bit towards our direction, she is supporting all of her weight on that leg, it should be solid.

- I still make this mistake a lot actually xD The breast closest to us is larger than the other one ^_^'

Form/layout etc -
The background could use a little more detail, it's hard to tell whether she's outside or in a green room ^_^'

I think it would look better with the lines actually, if they were a bit messy you could always use the pencil grain for a texture? I usually detest lines but sometimes they help tighten a picture up, also it's pretty hard to draw a cartoon - ish picture without them xD.

Like I said above, I think this is your best yet and I can't wait until your next one

I can send you a link to 'artweaver' if you'd like, it's a little like GIMP only every thing's in one window and it's more like painter than photoshop but I think you'd like the brushes it has, and coupled with gimp I'd imagine it'd be a pretty useful substitute for photoshop. (though your tablet probably came with photoshop elements or something similar, in that case we can be photoshop element buddies )

This crit may be a little harsh but I hope you know that I don't mean for it to sound cynical, condescending or rude at all ^_^' It usually takes me a while to write something that's easy to read, so if a paintover is something you'd prefer over a lengthy crit then I'd be more than happy to d a few.