It looks like “Easy Apache” handles both Apache and PHP. Only a guess, but you have recompiled Apache/PHP without the needed image libraries– either GD or ImageMagick. Without those, the server cannot physically resize images.
You can use a phpinfo() script to see if the libraries are present. If not, you will need to recompile– or whatever that “Easy Apache” system allows– and make sure the needed libraries are included. Maybe you can add modules one by one using that system. Not sure.