Admin meta Image Path

Unfortunately your question is still unclear after all the explanations, but based on your efforts, I guess you need to pass the image’s URL to a meta field or some sort of array.

So, turning your current code into this will fix the issue:

'img1' => '<img src="'.get_template_directory_uri().'/inc/admin/images/layout.png" alt="Image 1" title="Image 1">'