Same issues here! I can't choose from any existing galleries/collections. I tried setting up a blog page, product page & gallery section with images but nothing shows up on the "Use Existing Gallery" tab. Was anyone able to figure it out?
@tuanphan thanks for posting link to the Gallery Blocks guide. This guide says you can display content from a Gallery page, but in 7.1 there's only Gallery Sections. Does that mean it's not possible to add images using an existing gallery or collection?
Any help would be appreciated!