If the purpose is just to pay for pre-trial release of inmates, the simple solution would be to just release them and offer them reasonable payment plans. Or to postpone the fee until after they have had a fair trial ("I will only pay you if you treat me fairly according to the law" might actually incentivize the judicial system to treat people more humanely).

Locking people up for not being able to pay their fines/fees is literally debtors' jail. This was supposed to have been declared unconstitutional, but the practice remains, and the ACLU is fighting current cases.

https://en.wikipedia.org/wiki/Debtors'_prison