Well you can put HTML code into the txt file itself so you'd just take the images out of the *template.html pages' codes and put them in the txt file instead.
What happens with the txt file is, basically, anything inside is copied onto the specific archive page directly below the comic page. HTML code as well as keentags are processed accordingly and placed on the archive page.
What you could do, then, is in the text file make a new table so you have two columns for the author and artist notes, then end the table. On your index page, these will appear above your archive button and shoutbox.
Also, you spelled advertisement wrong on your dailytemplate