I see the white line now. Pls insert the following custom css in the Custom CSS tab in the theme options panel or in the custom/custom.css file.
#header { border-top: none; }
It will get it removed in the next update so that you do not have to repeat it.
For the thumbnail issue, pls see the code fix mentioned at the bottom of this post –
https://www.livemeshthemes.com/support/forums/topic/selected-post-snippets/