DMD generated exes' size differ from PE headers

[bobef]

I'm walking the PE header sections to find out the file size. I find the maximum PointerToRawData and add SizeOfRawData of the section to find where the exe ends. It works with the files I've tested. When compiling exe file with DMD 1.055 and -g there are additional four bytes after the last section. Why is that? Is SizeOfRawData wrong or there is something else at the end?

Thanks