Hide and seek

When I snapped this photo of the old warehouse building on the River Lune quay in Lancaster, as the Sun was setting (before the building’s recent redeveloping) I didn’t see anything unusual. However, as I adjusted the RAW file in Photoshop, there in the bare top-left window I suddenly spotted a small head popping up into view!
Who this youngster is I’m sure will always remain a mystery, but they will be around six years older than when they were accidently caught in this picture…
*Shot on a Canon 5d mk1 12mp dSLR using a Canon EF 50mm f/1.4 lens with settings at ISO-125, aperture at f/2, spot metering mode and an exposure time of 1/800 seconds*