Save to Photos on Mobile
You can save the post to your phone on the final "Caption Your Post" screen. You may need to scroll through the options to see the option to "Save to Photos." Don't forget to press the final "Share" button in the upper right corner to complete your post. The post should then show up in your photos/gallery app under a newly created "Ripl" album. Note: To save a post that you have already made, you'll want to go into the Post Details page, hit Duplicate in the bottom left, and then proceed with the instructions above.
Save to Computer
You can save the post to your computer on the final "Caption Your Post" screen. On the left side of the screen is the option to "Save to Computer." Don't forget to press the final "Share" button in the upper right corner to complete your post. On Chrome, I would expect your downloads to show up here: chrome://downloads/. If you use a browser other than Chrome, let us know and we can give you specific instructions for that browser. We would suggest trying on Chrome if you have any issues as Chrome works best with our web app!
For more information on saving drafts, check out this article: Saving A Draft