Being an dog lover, I have always liked signs with animals illustrated on the signs. Sometimes a company incorporated an animal into the theme for no apparent reason, or at least a reason I cannot determine the rationale today.
The Old Honesty tobacco brand certainly used the image of a Saint Bernard simply to tie into their marketing language as being “Always Reliable”. Remember, this sign was produced back in the day when the guidelines for any type of consumable products were not as tight as they are today. So tobacco, like so many other food products was probably not always up to the expectation of the consumer. In this case, the visualization of a Saint Bernard dog which we know is always considered a reliable work house type of dog was used to help illustrate this point. Unfortunately I cannot find a quick reference as to the manufacturer of this particular cut pug smoking tobacco.