The Clothing Resizer is one of many objects in the magic shop or can be randomly found in random life depending on what act of god wanted to be charitable or cruel to the one who found it. On the package usually it'll say something like "Tired of your clothes not fitting? Try using the Clothing Resizer!" It's functions are simple. It affects the BODY of the target and not their clothing. There are a number of options that the Clothing Resizer will allow including but not limited to: Fit, Baggy, and Tight. Now for technicality sake the target doesn't need to wear the clothing strictly speaking, just be in contact with it, and for one more condition it only effects the body part of the garment you'd normally wear the clothing on. Like you can't put a bra on a scrawny butt and expect it to grow... only the breast tissue would grow there.
There have been some complaints that the Clothing Resizer only resizes bodies instead of clothing like the name may suggest, and any complaints may be taken up with the council of magic item fraud... However you may find this exceedingly hard to do, and the results may end in... unspeakable results. So then?!?! Whose going to buy/find/be forced into acquiring one of these devices?