The hidden storage room is in the cell diagonally opposite the prisoner, to the left of a cell with a busted door (check the map and it should be obvious which wall section inside is movable), where you can find a couple kegs of explosives (one to clear the cave-in and another to open a short passage a little after that).
Specifically,
To get to the hidden storage room, there are a couple vertical wooden beams at the back of the cell, with a button on the left beam. After that there is another button (on the right IIRC) to remove another false wall.
The two small kegs of explosives inside are on a table, IIRC, and there is a bit of loot to collect.
There is no function to highlight objects you can interact with.
There is no built-in screenshot function, but there are dedicated programs that use fewer resources than Fraps (there is a 'snipping tool' included in
Vista and
Win 7, though I don't know if it will work for this purpose). With Beyond Divinity I used a program called PNGShot, but it has not been updated since then. I saved links for a couple others that I have not gotten around to trying yet:
Gadwin PrintScreen,
MWSnap, or check out some listed
here.
If you only have a couple screenshots to get, you can use the Print Screen button, and alt-tab or exit out of the game to paste the image into a graphics editor or viewer. Speaking of which, some image viewers include a screen capture function;
IrfanView does, but at least in v4.0 (latest is 4.28) you could not use the Print Screen button as a hotkey (other keys may not be recognized with a game running fullscreen).
