My index.php content is: "HELLO WORLD"

My myfile.php content is bigimage.jpg (10mb size and will load for 20 seconds).

On index page i fire $('body').load('myfile.php'); and I want it to wait till image is loaded (dont change HELLO WORLD text). 

And when image is loaded, then instantly replace old body 'HELLO WORLD' with image that is loaded at the moment.

something like: $('body').load('myfile.php',[change DOM when myfile.php is fully loaded]);