After the loss of my data a few days ago, I set the "Reserved Pictures Memory" to 0MB. The "Device Memory Limit" is set at the lower of the two options (12MB). Even if I had some pictures on the device memory, it still does not explain the memory leak which could only be rectified by a hard reset (and with it regaining more than 7MB).
I probably wait until an official OS release from RIM and/or BlackBerry. Otherwise, I am sure they will blame it on an "unapproved/unreleased" version.