Press a block to change color. To Save, click See Inside, then click Save in the project in the top right. Right click on the savecode list that appears, and click export. Follow the instructions there. To Load, click see inside, then click Load in the project in the top right. Then right click on the savecode list that appears, and click Import. Follow the instructions there. Then wait up to 5 seconds. You may have to click load after you select your saved file, if an image that is not your image appears on the screen.
All of the code is from mister-pizza. The only changes that I made are adding the save and load features. I also decreased loading times by putting it into a custom block.