Your image didn’t come through, so I don’t know whether it answers the question – but in case it didn’t let me explain in more detail.
When the image is uploaded in to the library, I can use the text widget on the banner wide when I can copy and paste the url of the image from the library in to an tag but the featured image image is a little different. I don’t want to be doing an tag in a widget for every post, instead, I want to be able to assign something in a widget that says, effectively “when it’s a blog post, use the featured image”
I am 100% using the Lavish Pro Child template (the problem seems to replicate on the parent template)
I’d rather not share the URL of the site just now on a public forum, but can email it separately. On your sample of the template, the section that I am referring to appears beneath the homepage banner image: http://demo.styledthemes.com/?theme=Lavish