Image shuffling with Arnol's cat map code correction

Hello, I'm working on implementing 2D Arnold's cat map of N x M images. The problem is that I can't get back the original pixel's values (i.e Arnold cat map inverse not working). Any solution from any freelancer will be paid for. I wrote the attached VB 6.0 code according to 2D Arnold's cat map equations fro shuffling and inverse. Code file: Shuffling [login to view URL] Thanks