One thing I always hated about summernote is how the default behaviour embeds images right in the HTML (as <img src="... base64 strings). It’s super easy, so of course my users go to town on this feature. However, it really bloats the rendered HTML and makes my mongoDB collection (where I store this stuff) almost unworkable. 
Anyway, there is a simple way to move the image to AWS S3 on the fly. I posted a quick and dirty Meteor-only solution as a comment in the original Github issue thread: Using amazon s3 storage with summernote
I hope someone finds this useful. Cheers.