Root Why are apps smaller on SD?

[BeachBumDeac]

Had a low phone space warning so I've been moving a bunch of apps I don't keep open all the time over to my SD card.

Why does the memory footprint of the app go way down when moved to the SD card? I had one go from 2.8ish MB to 800ish KB.

 

[lennyjew]

That's how much is left on your phone. Only 2 MB are moved to sd, the rest is left on the phone.