In this WP Builds Contribute episode Paul Cress shows us how he uses Adobe Spark to greatly reduce the amount of time that it takes to create his images.
Adobe Spark allows you to source common social media sizes, find free images and adapt your images, all in the web based interface.
It’s free and really easy to use and amending previous image templates could be a real time saver if you are creating images often.
You can find it here:
https://spark.adobe.com/