The Monkey can actually edit and save photos up to 16 megapixels. To keep PicMonkey moving super fast, we resize larger images to about 2800 pixels on the longest side.
You can change the PicMonkey default maximum size by clicking the Gear icon in the toolbar above your open photo. Choose from three different settings ranging 3–16 megapixels. You can also choose if you'd like to be alerted when changing the size may improve performance (this setting will be stored in your browser). Going forward, your images will only be resized based on your chosen setting.