I will try to give you the best measurements pixel by pixel that I can.

I will include my .psd because this was done in Photoshop Cs6.

NOTHING says Halloween then a Jack o' lantern with a screaming face.

horrifedpumpkin.psd
Download

Step 1: Setting Up the Page.

Open a new image 200 x 200
Select the pencil tool with the following settings.
Size=1
Hardness, Opacity and Density = 100
now go to "Edit" and go to "preference" and the click on "Guides, Grid, & slices"
A pop out should appear reference the settings in picture 3
then zoom in till you can see the pixels clearly but have enough to work.

Step 2: The Outline and Inside

B95E22 <----- color code for the color I used

P.s i set up guides down the center so that i could do half the pumpkin the flip it to make it go by faster.

If u do it by half it starts with one pixel instead of 2 as the picture but this is perfectly equal pumpkin So look at picture 3 for the pixel by pixel placement.
the color code for the fill is B95E22
use the fill bucket tool to fill the inside.

Step 3: The Stem

create a new layer
Start with the outline using 5c341a color code
Follow picture 1 for pixel by pixel measurements.
then close off the bottom with 884f29 color code then fill it in with the same color

Step 4: The Re-Size

Okay a bit of trickiness is about to occur.

on both the stem and pumpkin layer you will need to make Duplicate layers then merge the to duplicate layers together
then while holding CTRL key click the pumpkin layer with the stem layer that you just merged, it should select the whole thing,
next while holding CTRL hit T that should bring a box around you pumpkin then go to where the menu area is you should see to boxes one with a "W:" and the other next to it " H:" with both having 100% in them change both to 400% and bam re-sized.

Step 5: The Face

:D your almost done

okay use color code B95E22
and use the pixel by pixel from picture 1

if you did it by half then you can flip

Now make a duplicate layer of the mouth shape
then while holding CTRL click the image on the layer panel at the bottom right then with the fill bucket full it with color code 7e4825
then hit CTRL T and move the shape over 4 pixels to the then hold CTRL and click the layer under it the original mouth shape
then click back on top the darker mouth shape then right click the selection and click "inverse selection"
then click on the eraser tool and erase
Now to make the eyes make a duplicate of both shapes for the mouth
then merge them together.
Now CTRL click that new layer the hold CTRL T
now go to the top and re-size it but inputting 50% to both w and h then hold CTRL J
then hit v and move the other eye over and bam complete.