Circuit-Swap mechanism on going (BMP->PPM)
Magic numbers

What is the significance of 18, 19, 22 and 23? They must be defined in terms of bitmap file header and bitmap info header
Correctness


According to a spec, bitmap width and bitmap height are 4 byte integers. The code accounts only for 2 bytes.
The code completely ignores colour depth.
The code is unable to deal with palette-based bitmaps.
The code completely ignores possible DIB compression.

Style


All-uppercase words are usually reserved for macros. Normal variable's identifiers should be in snake_case or camelCase.
What is the purpose of typedefing DWORD?
You should at least make your snippet into a function. Otherwise it is completely useless.