phpthumb_document_root
allow_forward_across_contexts
Name: PHPThumb Document Root Type: textfield Default: Available In: 2.1+
Set this if you are experiencing issues with the server variable DOCUMENT_ROOT, or getting errors with OutputThumbnail or !is_resource. Set it to the absolute document root path you would like to use. If this is empty, MODX will use the DOCUMENT_ROOT server variable.