The volume occupied by study files is now detailed by type of stored files in the General tab of the Details on study view.
The total volume is also displayed in the Manage studies list view. The list can be ordered by this new column, and by hovering over it, the detailed volumes are displayed in a tip box.
Note that these values corresponds to the size of uncompressed files. The size of exported archives can therefore vary greatly.
The total size calculation is detailed in the wiki : https://github.com/fli-iam/shanoir-ng/wiki/Study-storage-volume