Q? Whenever I use the navigation to go back in the archive it displays a 404 page.
A. Go to Settings -> Permalinks and click save. The reason is – at this time when you activate Comic Easel, WordPress doesn’t know how to handle the custom post type yet. When going to the settings – > permalink int he wp-admin you are initiating the re-evaluation of the structure to which can be used.
Q? The theme I am using does not have ‘featured image’ support for it.
A. This is most likely the theme developer hasn’t added it yet or the theme was made a long time ago when it wasn’t available. For those themes you can add this bit of code to the functions.php of that theme and it will enable support for it.
add_theme_support( 'post-thumbnails' );