Most here probably know the first modern comic books were printed in 1933, though there were collected reprints (in hardback) as far back as 1897. The modern format was similar to the dime novel. Comic strips go back as far as 1842 (sez WP).
So, could comic books, in their modern size & format, have appeared earlier? Could they have accompanied, or even supplanted, the dime novel (or Brit penny dreadful)? What advances were needed to produce the modern format, & could they have happened sooner?