Well, there's only one thing one can do in this situation: write a script which trims pictures from surrounding whitespace. You can find the script here: https://gist.github.com/4649500#file-whitespace_trimmer
As this script is written for bash, it only works on Linux systems. I guess there's some nasty way to get bash running on Windows too, but hardly anyone still uses Windows nowadays, right? Moreover, you need ImageMagick installed.
If all of the above applies to you, you can run the script like this: