Looking at the pictures, it could a different woman in these shots. In some I look willowy, in others like a pregnant hobbit.
My investigation was helped by Dr Melissa Kao, director of Magic Mirror, which supplies innovative camera mirrors to retailers such as Harrods and River Island.
"Shops sometimes employ tiny tricks to make you look as good as possible, which include tilting mirrors upwards. This elongates the look of the body," she reveals.
"The mirror may appear flat against the wall - but even a tilt of just a couple of millimetres can be enough to give a bit of extra length to the legs."
Dr Kao also says mirrors may have slightly different tints, some of which will give the face a more healthy glow.
"Shops often use a 'ring flash' where strip lighting creates a halo effect - much like you'd see in those old-fashioned make-up mirrors set with bulbs. It gives a shadow-free reflection and an even complexion," she says.
They say the camera never lies, but the one thing I've learnt is that changing room mirrors do.
1. Gap
A fat tummy but I really can't complain
Amanda says: Gap has been a favourite of mine for years for its honest and simple clothes. I look pretty normal here, with a bit of a fat tummy. The cubicle was spacious and they had a "help" button. I didn't need it. As one of my male friends is fond of saying: "I wouldn't chuck her back."
Expert says: This good-sized - 5ft 1in x 4ft 3in - oval-shaped and white changing room creates a reasonably natural reflection and a daylight-like feel. The two whiteish strip lights set behind the mirror make another ring flash, banishing shadows and evening out complexion.
2. Topshop
I look like a Lithuanian shot-putter
Amanda says: I know this is supposed to be a shop for teenagers, but how many of them could withstand this harsh reality? I look like a Lithuanian shot-putter hiding her money belt around her waist.
Expert says: This large mirror, measuring 8ft 3in x 3ft 3in, runs from ceiling to floor and is flat against the wall with a large fluorescent light directly above your head.
Without other lights to diffuse around the immediate area and soften the look, all your imperfections will be very much on show.
3. H&M
Praise the lord! I've dropped a dress size
Amanda says: This cubicle was near perfect. It was roomy, had soft overhead and front lighting, and was flattering overall. Though I did detect a bit of trickery as it made me look a size ten, not 12.
Expert says: This shows how investment in mirrors can really pay off.
Two yellow strip lights set into either side of the mirror create an excellent ring flash effect - and makes Amanda's waist look more slender.
Floor space measures 3ft 10in by 4ft, giving plenty of room. A combination of off-white walls and a small mirror to the left further disperse soft light throughout the cubicle. The garment and face look airbrushed.
4. John Lewis
Am I really this lumpy?
Amanda says: They should be done by Trading Standards for their motto: 'Never knowingly undersold.' They undersold me! The overhead lighting was unforgiving and the mirror, well, let's just say I sincerely hope this is not what I look like in real life. There was a button for help and I hope that included a psychiatrist.
Expert says: This mirror sits absolutely - and unflatteringly - flat to the wall in this changing room, which measures 3ft 6in x 4ft 7in.
The lighting is far too strong. Two LED spotlights and one strong fluorescent light beam down from overhead and mercilessly emphasise every imperfection, adding years to the face and rucks and folds to a previously smooth-looking frock.
When light falls downwards onto, for example, the very slight curve of a stomach, it creates a dramatic shadow beneath, making Amanda look lumpy. Though the cream colour of the wall slightly softens the glare, the dark grey curtain doesn't help, as this absorbs rather than reflects light.
5. Debenhams
I can even see my undies
Amanda says: I have to admit this is a pretty fair reflection of me. No washboard stomach, a hint of Jonny Wilkinson's thighs, you can even see where my undies cut into my hips. I should have worn a pair of Spanx.
Expert says: The full-length mirror is the smallest of them all and ends just a few inches above the head, which makes you look a teensy bit taller. The room measures 4ft 8in x 5ft 8in, giving plenty of space to see your reflection from a realistic distance. If you were chatting to someone on the street this is how you'd probably look to them - as long as you were wearing heels!
6. Zara
Who ate all the pies?
Amanda says: Initially I loved the large dressing room, which could easily fit four friends in as well, but the lighting was horrendous, throwing shadows over my tummy. I looked as if I'd not only eaten all the pies, but stuffed a few down my dress for later.
Expert says: The fitting rooms appear elegant, with plenty of space - the floor is 7ft 8in x 3ft 4in - but they are inexplicably fitted out in shades of grey, with dark charcoal curtains and light grey walls. These colours absorb light and produce an unforgiving reflection. The overhead spotlights create appalling shadows. This ages the complexion and every lump and bump is exacerbated.
7. Fenwick
It's me with Elle's body
Amanda says: Flawless skin, hardly a hint of turkey neck and Elle Macpherson's body - I'd love to think this is how I really look. Forget the rest of the shopping - I want to buy this changing room mirror!
Expert says: A genius changing room, measuring 4ft 11in x 3ft 6in. The mirror appears to be fabricated from what we call low iron.
All mirrors contain iron, and this gives a very faint greenish tinge to skin. If there's less iron present the mirror gives more of a healthy and natural glow.
The yellow lighting complements this - there is a spotlight above the mirror and a flattering ring flash created by two long yellow strip lights behind either side of the mirror.
8. House of Fraser
I've aged ten years
Amanda says: What can I say? I look like a run-to-seed drag queen. This was the most depressing changing room, cramped and with horrid lighting. I looked fat, it bleached my face, ageing me ten years, and made my hair resemble straw.
Expert says: The room measures 3ft 10in x 4ft 9in. It looks as though the mirror is slightly tilted forwards from the top, shortening the legs, but on closer inspection the problem is clearly the large bright spotlight directly above the head, which looks well over 100 watts (normal household lights are more like 40 watts).
The colour of the dress is bleached out - and the merest curve looks positively gargantuan.
9. M&S
This is the cubicle from hell
Amanda says: My 30-year love affair with M&S almost ended in this changing room.
The store was full of tempting new arrivals, then into this reverse Tardis, which was squashed and badly lit.
Note to boss Marc Bolland - why spend so much time designing fabulous, affordable clothes just to put us into the cubicle from hell, which would only make us change our minds about buying them.
Expert says: At 2ft 10in x 3ft 8in this is the smallest changing room.
Where the shadows fall and the size of the room mean you probably need to stand closer to the mirror, which is set flat against the wall. This means you're probably going to get a frustrating and unflattering view.
There is huge discrepancy between the price of mirrors from shop to shop. This would probably only be about £100, but a more expensive one with rose tinting - where a reddish mineral, selenium dioxide, is added to give a rosy glow - would cost more like £2,000 and make you look and feel like a million dollars.
10. Selfridges
Not a bump in sight
Amanda says: I looked positively youthful and glowing, with hardly a lump or bump in sight. And somehow I looked not only six inches taller, but a dress size smaller.
Expert says: Two long yellowy strip lights run down either side of the mirror, creating that flattering ring flash effect. Here it cinches in Amanda at the waist as the light focuses the eye on the centre of the mirror.
Though there is some ring flash with other lighting, only Selfridges and H&M had the strip lights set in front of the mirror, which probably explains why they were the most effective.
Generous cubicle dimensions - 4ft 5in x 4ft 11in - mean that you can stand further away from the mirror and get a clear view of exactly what the outfit looks like.
The background is orange, which emits a warm glow and makes skin look healthy and tanned.
- Daily Mail
