Thread:Extension talk:Widgets/Trying to get property of non-object

I'm seeing this PHP Notices recently:

Undefined index: size in ../extensions/Widgets/compiled_templates/ba811dbfd89414d874993a209b5e2eb71ad14d2d.wiki.Google Presentation.php on line 30

Trying to get property of non-object in ./extensions/Widgets/compiled_templates/ba811dbfd89414d874993a209b5e2eb71ad14d2d.wiki.Google Presentation.php on line 30

How can I clean these up?