Version:           1.0.0-beta1 (rev.: /usr/bin/svnversion) (using 4.2.4 (KDE 4.2.4), volkerdi@slackware.com)
Compiler:          gcc
OS:                Linux (i686) release 2.6.28.10

As a default images should be loaded in alphabetical order. e.g. it is more logical to see first screen like this:
source image | target image
old-1.jpg    | new-1.jpg
old-2.jpg    | new-2.jpg
old-3.jpg    | new-3.jpg

right now after loading files it is like this:
source image | target image
old-3.jpg    | new-1.jpg
old-2.jpg    | new-2.jpg
old-1.jpg    | new-3.jpg

of course the list can be sorted but still this would be an extra unnecessary step.