Talking about small scale art, the Open Eye Gallery in Edinburgh has an annual show in December called "On a Small Scale". It is an exhibition of small postcard sized (15-21cm) works of art by well known and invited artists. There are four walls filled with all these works, perhaps a couple of hundred in total (I didn't count). All media and all small. This type of exhibition is my favourite because of the huge variety on the walls: there's always something good, sometimes great. Another reason to look forward to December.
Path to the Loch, Argyll, by Robert Maclaurin, oil on linen on board, 15x21cm
Slow Morning, by Gertie Young, mixed media, 15x21cm