There is a hidden folder at Roundscape\www\img\pictures containing all the cg. You can find it by going into the roundscape folder and do a windows explorer search for a character name for example clawyn. You should see the results and with right-click on it you can go to the file path of the picture.
BTW, using your advice I looked at Mansion scenes we tried so desperately to unlock. There are:
1) corrupted father on femPC;
2) pure daughter with malePC;
3) pure daughter with femPC;
4) corrupted father on daughter;
5) corrupted mother on son;
6) pure mother and daughter with malePC;
7) corrupted mother and daughter with malePC.
This patch introduced 6 new scenes. Here we see 7 scenes. But scenes 6 and 7 are basically the same. Which almost certainly means that all 6 scenes are identified and are Mansion-related.