Since you are getting downvoted. I'll explain. On TV, you see inmates in one piece jumpsuits. In reality they are more like shitty scrubs.
The reality is the percent of people who are processed in a jail, do not become prisoners. I.e. you get a DWI, you stay until sober and if there is no bail, you go home and never see a true prison cell.

You are in a holding "tank", (bigger than a cell, many people), and then held in a release area. During that while time, you keep your own clothes, but belts, shoelaces are etc. So going through a minor infraction where you arent jailed means you see a lot of people in their own clothes, sans belt, so lots of sag. This is the "jail" most people experience.