Canva is a simple to use tool that allows users to easily create professional looking images. I signed up as soon as I heard about the site and was creating images as soon as I got my account confirmation. The interface is intuitive, the templates are helpful and the final results look great.
My only reservation about Canava is that many of their stock images cost $1.00. I'm always hesitant to post things that can cost money because this creates some obvious issues for students.
However, Canava does offer many free resources and they were very quick to respond to my questions. I asked about the potential of free educational accounts. Those do not exist yet, but the Canava staff did give GarrisonSites permission to share this VIP link. It will give you instant access to the site (no ~48-hour waiting after you sign up) and $10.00 in credit to spend on your creations.
You can create everything from posters and business cards to Facebook cover photos, presentation graphics, photo collages and holiday cards. Give it a try.
You'll be impressed by what you can create.