Related issue here:
Searched media_gallery issues for similar or same/duplicate issue here:
Consider photography, social media, community sites based on media_gallery using media 7.x-1.x whose owners want to move to media_gallery using media 2.x for benefits of bug fixes and new functionality. How are they going to migrate 1000s of photos in galleries to be on their new site running media 2.x?
My suggestion would be a utility to export into an open format (jpegs+xml) and a tool to re-import it into the media 2.x site.