DropBox gallery is an excellent idea for an object. I prefer to put photos in a shared folder instead upload code every time I have a new photo. 

I want to suggest some ideas.

1 - Extend to Drive and OneDrive

2 - Put more options on object, like order by row instead of column.

3 - Choice to order files from data (new / older on top), name, size, etc. 

4 - If possible, turn visible every file on shared folder, videos, pdf, etc 

Congratulations, keep good work