Via Nature World News:

Researchers at Georgia Institute of Technology have painted the smallest-ever image of Mona Lisa. The painting was created using an atomic force microscope and a process called ThermoChemical NanoLithography (TCNL) and is painted on a substrate that is 30 microns in width or about one-third the width of a human hair. (Source)

(Pic above is not actual size. Click on it for an enlargement of the... tiny micro version. Or something.)

Dust mites are gathering around it, going "Ooohhh" and "Aaahhh."