Warning - imagecopyresampled() expects parameter 2 to be resource (1 reply)

I received this message after upgrading to 2.11.0 and adding a custom logo.

WARNING CoreAdminHome[2015-02-19 04:42:12] [fcf03] /www/piwik/plugins/CoreAdminHome/CustomLogo.php(223): Warning - imagecopyresampled() expects parameter 2 to be resource, boolean given - Piwik 2.11.0 - Please report this message in the Piwik forums: [forum.piwik.org] (please do a search first as it might have been reported already)

edit:
I have reproduced this error when Piwik did not like the png file and I received the following error.

WARNING CoreAdminHome[2015-02-19 05:03:38] [01db7] /www/home/piwik/plugins/CoreAdminHome/CustomLogo.php(202): Warning - imagecreatefrompng(): '/tmp/phpEfv0yj' is not a valid PNG file - Piwik 2.11.0 - Please report this message in the Piwik forums: [forum.piwik.org] (please do a search first as it might have been reported already)