I bought the medium bag in purple. From the dimensions on the webste the medium is not that much smaller. It was plenty big for a family of 4 with wetsuits, bottles of water cameras and a few other things. Hope this helps!
ME (33) DF (33) DS (10) DS (3)
Offsite 2/89 Offsite 5/98 Pop 7/08 Pop 12/09 CSR 8/12 DCL Fantasy 5/14!!