In Oscar Wilde's The Picture of Dorian Gray, the eponymous subject keeps his youthful looks while the vagaries of age are visited upon his portrait in the attic.
Now a digital version of Wilde's idea is being developed to show you what you will look like in five years' time if you take no exercise, eat too much junk food and drink too much alcohol.
At Accenture Technology's lab in Sophia Antipolis, near Nice in France, a flat-screen LCD TV linked to a set of cameras and a powerful image-processing computer replaces the portrait described in Wilde's novel.
Initially the system acts just like a sophisticated "mirror" in which an image captured by a wireless camera is displayed in front of you.
Its main purpose is to conjure up a computer-modified image of the effects of overindulgence at the press of a button, says Accenture lab director Martin Illsey.
These webcams will feed images of your everyday activities to a computer running software that is able to recognise different patterns of behaviour.
Once the computer has built up this profile, a different software package will extrapolate how this behaviour is likely to affect your weight in the long term.
If the computer feels you are eating too much, it will calculate how many pounds to add to the image of the person standing in front of the mirror.
"Helping people visualise the long-term outcomes of their behaviour is an effective way to motivate change," says B. J. Fogg at Stanford University in California, whose team has developed sunglasses that show the effect of too much sunshine on the skin.
"I don't think any system which presents a negative image of the user will be taken up by many people," predicts Cliff Randell, an expert in ubiquitous computing at the University of Bristol in the UK.