Believe it or not, readable 38 lines !
Check it out:

poisson.m

Usage:
poisson( 'monalisa.png', 'venus.png', 'mask.png' );

Paper Link: Poisson image editing

Input Images


venus.png


monalisa.png


mask.png


------------ Result --------------


result.jpg

mailto: &@verygood.aid.design.kyushu-u.ac.jp (replace "&" with "and")