WordPress error: Image could not be processed. Please go back and try again.

If you get an error saying

Image could not be processed. Please go back and try again.

when you try to put a new custom header image for WordPress theme 2010 on a server using Ubuntu the following may help:

apt-get install php5-gd

once it installs then

invoke-rc.d apache2 restart

This will provide php the ability to manipulate images that WordPress is trying to use.