Rip van Winkle's dog bears a passing resemblance to Pluto, Disney's canine creation. At the time this short was produced such 'borrowing' was commonplace, as the concept of intellectual property law was still in its infancy.
A man who leaves his wife and a (presumably unwed) dog having puppies were bold ideas in the early days of the emerging production codes.
The little people are shown ogling "French postcards," which were typically small, postcard-sized pieces of card stock featuring photographs of nude or semi-nude women. Such erotic cards were produced in great volume, primarily in France, in the late 19th and early 20th century. The term was adopted in the United States, where such cards were not legally made.
Vitaphone production reel #6373.
Popular entertainer Rudy Vallee is spoofed here by one of the little people, including his signature megaphone.