See report in http://forum.piwik.org/read.php?2,79483
When generating PDF reports, if GD is not installed, the error is returned. Instead, we should show to the user a proper error message that suggests to install GD.
If this happens in the cron, we can make sure that the error returned as part of #2440
(In [5054]) refs #2577
tcpdf/tcpdf.php already has checks in some places for function_exists( some_gd_function ). This can probably be fixed upstream.
We already have an installation system check for gd, and warn when it's not present.
Matt, I think you still have the 'imagick' extension. Looking at the code path, 'gd is the fallback if the 'imagick' extension isn't available.
Can we defer to 1.7 and update libs/tcpdf at the same time?
It works now, graphs are not displayed when no GD (but icons still display in the report which is nice)