C++ Project Compiling

Hey guys, ive been coding on my D3D hook,but since the base was done,i release build it.

Its only 27kb for a whole file ?

It was 584kb but it went from the one to the other day to 27kb,any ideas why this may be?
Ive checked my compiler options,all correct.
But if i build iit gets this adnormally small.

Tips will be welcome
Thanks

on debug build it compiles all debugging info with it, u can smaller your projects by Release build.
Debug build includes browse info etc, so when your hook crashes u can press debug and get to the line in your c++ code where it crashed. in Release build this is not possible.