Hi Kate,
Thanks for contacting us!
Currently Ribbet doesn’t host your images, and so it’s not possible to get a URL to the image on our site. Most social media sites will allow uploading (Facebook, Google+, Twitter etc).
If however the particular site you want to share on doesn’t, what you can do is upload the image you’ve saved from Ribbet to a free image hosting site, such as Google Photos or Flickr, and then share the URL from there. Ribbet lets you save directly to Google+ and Flickr (see the sub-tabs after clicking the top middle Save tab), and if after saving you follow the link to your photo on one of these sites, you can then share the URL to it.
Let us know if you have any other questions!