According to a January survey by the Email Experience Council, fewer than 50 percent of marketers create emails that render appropriately. About one in five emails are -- you guessed it -- invisible and ineffective due to blocked images.

Marketers, of course, may not have the slightest clue that their emails aren't arriving in the inbox as designed, unless they face such startlingly low open and click-through rates that they dig for answers.

Does your email look like this?