i am gonna use Photoshop CS5 here ,, which is of great use specially in merging a pic .
if u dont have adobe photoshop go to Adobe.com simple :) ( u might need to spend a lil more )
This zombie trying to cut his head and wanna die and end up his undead life. he might have seen his gf's head in some dustbin
i always try all-most to start from scratch
Step 1: Getting Started : Open PhotoShop
Goto File >> New >> height 780 pixels , Width 1024 pixels
i dont have chain saw so i downloaded one picture of person holding a chainsaw.
if u have a chainsaw come on hold it and ask ur mom to take ur picture n tell her ur gonna cut ur head !! she wont mind !!
(jokes apart : do not switch on ur chainsaw )
>>>one u got ur pic clicked just remove its background using Wand tool, marquee tool, or some other selection tool n press delete to erase pic
>>> i then downloaded a chainsaw which i feel was good for scene , i brought it in the scene to match the size and position .
NOTE : Make a duplicate of ur layer which u feel is gone wel n u can perform a mistake later on , also keep ur layers named .
here i duplicated the -man+old chainsaw- layer then i eased the white color from background. and Erased Old chainsaw
Step 2: !! Chainsaw Should Cut Ur Head Now !!
We are gonna use Puppet Wrap in edit menu or in image menu
in this tool u just feel like ur pic is like a chewing gum floating in air and u can fix some points in pic
ehen u have fixed some points just click and drag to stretch en the image
at end when u done make a series of back to back layer of chain saw and head because this will let u to have it in ur head ,
single layer wont do this , it will just look like its behind ur head , but duplication n bring it to front will solve purpose
after that just erase some parts of head so that it look like now the chainsaw is in head.
Step 3: !! Coloring Head !!
u can do it with simple brush tool.
>>>> Next use Smudge tool to open his mouth
in this i have downloded some brushes from website http://brusheezy.com/ and search for a lot more brushes
i searched for cracks , Blood Spatter, Liquid flowing etc which may help to deal with brushes
example : http://www.brusheezy.com/brushes/38422-uh-oh-accident--splatter-brush-pack
Adding Brush is simple just drag and drop brushes.ABR on brush tool then u can see it in Brush library.
one u got a dark red crack on ur head
now u just need to darken its edges.
you can just use Blending properties with inner shadow
>>>just play around with inner shadow ,outer shadow, etc try using outer inner glows as shades of red
Now all u have to do is add some ugly skin,Torn skin , Bones (not used),some bullet holes (not used ), some stabbing of weapon(used as AXE on back)
Step 5: !!! Axe-ing !!!
>place the axe behind the back erase back
>erase some parts of back
>do it red and then its done
Note : give at end a over all touch to pic so that it look scary and bloody :)