hi, i need to reconstruct an image from 4 other given images

[skicker]

i need to make the 'result' image by using the 4 other images. you dont have to use all of them.
also you can use 1 picture more than once.
you are alowed to sum,multiply and substract 1 pic from another. also the max treshold is 255 so you cant get 300 or 540 ..etc.. (0-255)
for example 150 150 150 + 200 200 200 = 255 255 255
*any picture is made from R G B channels

the question is- how to i do it? im new to DIP and I got this in a job interview.
any suggestions of the algorithm will help me alot )

[fmw42]

It should be just a case of remapping colors and/or (binary) masked composite or use of transparency and flattening. But it would help to prototype if you provided each of the 4 input images and the output images separately. See -fill onecolor -opaque anothercolor and -fill onecolor +opaque onecolor.

http://www.imagemagick.org/script/comma ... s.php#fill
http://www.imagemagick.org/script/comma ... php#opaque
http://www.imagemagick.org/Usage/color_basics/#replace
http://www.imagemagick.org/Usage/compose/#compose