Visuals are very important in marketing and like with email marketing, the stats are there to prove it. One month after the Facebook timeline format, which relies heavily on images, was introduced, engagement rose by 65% (source) and articles that feature images get 94% more views (source).
There are more arguments that support the importance of visuals: the human brain processes visual information 60,0000 times faster than text and 40% of people respond better to visual information to plain text (source). Also, 67% of customers prefer product images to lengthy descriptions or product reviews (source).
Still, designers are not always available or might have a fair amount of work on their hands already. You need a tool to help you create visuals for blog posts, social media or even banners quick and easy, without having to spend a lot of time.