Information graphics or infographics are graphic visual representations of information, data or knowledge intended to present complex information quickly and clearly. They can improve cognition by utilizing graphics to enhance the human visual system’s ability to see patterns and trends. The process of creating infographics can be referred to as data visualization, information design, or information architecture.
Piktochart is a web-based tool that has six decent free themes (and a whole bunch more for the paid version) for creating simple visualizations. You can drag and drop different shapes and images, and there is quite a bit of customization available. You can also add simple line, bar, and pie charts using data from CSV (or manual entry). You can export to PNG and JPG in either print or web quality. Note that with the free version, you get a small Piktochart watermark on the bottom of the PNG / JPG downloads.