Here's an idea for your libertarian brain... Let's make them liable for any images that would mislead a customer. If you offer a picture of a big, juicy, appetizing Whopper in your ad, you better deliver something that is very close to that when I walk in to your store.
The system you so hilariously defend depends upon customers with accurate information. Lies break the "free market" and cause it to be skewed in favor of the lairs. In most cases, it favors the company/corporation.