I’m certainly extremely sceptical about these, and would never order from such companies.
I know from experience how very good inferior clothes can be made to look. Many, many years ago, when dh and I were living in Cyprus (and I was a small size 10!) I had the occasional job (a fiver a day when we were stony broke) modelling for a commercial photographer.
One such job was shots for a clothing catalogue.
The clothes were pretty cheap, nothing really wrong with them, but I was stunned to see how amazing they looked in the photos.
One I particularly remember was shot on a green area in front of the Nicosia Hilton - me in a in dreamily-drifting short of shot, in a long evening dress that in the photo looked gorgeous and expensively glamorous.
In reality it was cheap material, pinned all up the back to make it fit me!
The photographer was great fun and very clever in the effects he could create with all sort of makeshift props, for whatever it was the advertiser wanted. A couple of expat friends of mine also did it, and we always enjoyed the day, not to mention the fiver.