I was very impressed by the image resizing demo you see here:
So when I saw that there is a Gimp plugin for it, I decided to try it out. Installation was a breeze thanks to MacPorts, my first experiments worked but when I wanted tor draw a mask, the Gimp crashed. This was due to the issues documented on, and fixed by, the XDarwin page on the x.org wiki.
So anyway, here are the results. First the original photo of people at the beach:
and again, but with the kid selected for removal and the width of the image reduced:
Notice the stretch of empty beach is shortened, yet both the people above the kid as well as the dog survived intact.