Instagram share improvements

Sharing on Instagram is now possible with more than one image. When you upload more than one image, the user will be presented with an option to download all the campaign's images and a button to open the Instagram app so they can start creating their multi-image post.

Additionally, this same flow makes it possible to share to Instagram using a web browser (on your phone, laptop, etc.) instead of our mobile app. These users will be presented with the same dialog that lets them open the Instagram app or website to create their posts.