You don't necessarily need only paintings as artwork. You can put some floating shelves near the dining space with some good crockery like plates or tea sets which can be used for occasions as well. On the wall in the living space you could keep either traditional or modern show pieces.

Regular window size 4width X 4 height floor to window sill 3' kitchen window size 4 width X 3 height floor to window sill 4' if low sill means stove burner of due to air

Ardhendu, It depends on the overall size of the property and also the location. 12x12 could be ok as the guest room but it may be called smaller when it's a master bed room. Thanks, Nitin Cornerstone Designs, Bangalore.

Hello sir, may I know where is your site located at?