Briefcase supports most major file types, including JPEG, GIF, BMP, all Microsoft Office file types, MP3, Real Media, WAV, AIFF, HTML, and numerous others.
Briefcase folders are actually the same thing but their contents are displayed differently.
If you create an album in Photos, you will create a folder in Briefcase. Photos only shows photo files, such as JPGs and GIFs. Any other files will be hidden within photos. You have 25MB of space to use for all of your briefcase and photos files. Currently, we support a maximum file size of 5MB per file.