An important thing to remember about creating infographics is that the actual design part comes closer to the end of the process.
A 5-Step Guide To Creating Compelling Infographics of Your Own is a good example of the steps to take for your infographic, regardless of whichever tool you use to create it.
If you don't want to experiment with the other tools, then PowerPoint is a great way to create an infographic. You can create shapes and text blocks and position them wherever you want, use the included clip art, or import your own images. How to Make an Infographic for Free with PowerPoint has some good points for how to get started on setting up your "slide." There are plenty of online guides or tutorials for using PowerPoint this way.
The Compound Interest graphics are done in Adobe Indesign and Illustrator, so those are definitely options if you have access and are comfortable with them (not sure about the learning curve on these).Here some other infographics tools. All of these are free, but offer premium versions that will charge for additional features: more images, greater privacy controls, etc.