Class Discussion Point: If the painting burned down, how do we know it ever existed or was as large as claimed?

Follow Up: The largest painting now in existence is The Battle of Gettysburg, completed in 1883. It took Paul Philippoteaux of France and 16 assistants two-and-a-half years to paint the 410-foot-long picture. It is 70 feet high and weighs nearly five-and-a-half tonnes. The painting is now in a private collection in Winston-Salen, North Carolina, US.
Patronising Closing Remark:
"Size alone, of course, is no guide to quality."
