Hey hhagen, it seems that some of your thumbnails use the url http://www. others use http:// without the "www".
You can easily check this out when you hover over your thumbnails, on the left bottom corner on chrome you can see the url it leads to.
What you can do is visit your wp-admin without www. and re-insert the project thumbnails.
Also maybe in your web-host you can configure the domain to only use http:// without www.
Also you should probably use a more recent version of lay theme, I sent it to you via email.
I know this http:// / www. issue is kind of stupid and I'm working on fixing that for a later lay theme update.