Use photoshop or any other imaging software.
i personally use Photoshop.
I had a similar problem for another application, this is what I did in
photoshop:
1)open original photo
2) select all > copy
3) create new file with dimensions of old file and select transparent
background
4) paste original into new
5) select white space and delete it
6) save new file.
hope this helps.
Diego
