The old trope among actors and TV personalities says the screen "adds 10 pounds." Well, you're (probably) not a TV star, but there are plenty of other ways to gain 10 pounds without trying. Losing the weight is harder.

Let's be honest. Who wouldn't love to shed a bit of body fat? It's just the motivation that's a problem. New Year's resolutions are dead by the 15th January, and your summer diet doesn't make it past the first barbecue of the season.

Perhaps the best motivation is visual. What if you could see what you'd look like if you lost (or gained) a few pounds? It might just kick you into action.

WeightMirror Is the Motivation You Need

WeightMirror (no longer available) is a free tool that lets you upload an image, remove or add weight, and see the results. To use the app, head to the WeightMirror website and select either Upload from Computer or Upload from Facebook to import your image.

The tool is most effective if you use a full-length body image. I don't have any on hand, so I'm going to demonstrate using the website's example model.

Before you start making changes, enter your current height and weight. You can enter them in imperial or metric measurements. To see the effect of weight loss or weight gain, slide the BMI indicator on the right-hand side of the screen.

Check out the results in the images below.

Current:

40 pounds lighter:

20 pounds heavier:

When you've finished playing with the slider, you can use the on-screen buttons to share the results on Facebook and Twitter, or to email them to a friend.

Does a tool like this motivate you to download the best workout apps and lose some weight? If you're too skinny, maybe it spurs you to eat a little more? Or do you find other methods to be more effective?