Possible Clues:

• Concise digit, secure
• Type of sketch taken from thin album
• Digital sketch?
• Brief, as a description
• Brief description
• Sort of sketch one won't want to go under the hammer
• Miniature person getting from A to B in the end
• Sketch which may be varnished?
• The sort of little sketch to have on hand
• Kind of sketch that shouldn't come under the hammer