I've written about several tools that will let you do this easily. Now Adobe has released Spark, a creative tool that makes this (as well as some other digital creations) simple with very attractive results.
I created this video tutorial that shows the process.
There are Adobe Spark apps for iOS and Andorid as well. Each app creates one of the three project types the web app can create. This particular project is called the Post.
If you're interested in more resources about this image with text project, see my Project Pack about it here. The post with all my Project Packs can be found at this link.