LPS-37506 - Theme thubnails are screenshots of the old ones

Hey @ronaldf10,

Attached is an update for http://issues.liferay.com/browse/LPS-37506.  Can you check the web content images to make sure they are the same?  We noticed a box shadow on the default one, but not on the light/dark color schemed ones.

Please let me know if you have any questions.  Thanks!