BITMAPINFOHEADER bih = {0};
    bih.biBitCount = bmp.bmBitsPixel;
    bih.biCompression = BI_RGB;
    bih.biHeight = - bmp.bmHeight;   // set this to negative

unsigned char* bgra2rgba(unsigned char* buf, DWORD size)
{
    if(0 == size % 4)
    {
        unsigned char* ret = new unsigned char[size]; // new alloc is only need for my own project
        memcpy(ret, buf, size);
        DWORD all_chunks = size / 4;
        for(DWORD i = 0; i< all_chunks; ++i)
        {
            ret[i*4+2] = buf[i*4]; // swap b, r
            ret[i*4] = buf[i*4+2];
            ret[i*4+3] = 255; // alpha channel: XP need this
        }
        return ret;
    }
    return 0;
}

Compiling screenshot v0.0.7
error[E0554]: `#![feature]` may not be used on the stable release channel
  --> [...]\github.com-1ecc6299db9ec823\screenshot-0.0.7\src\lib.rs:15:1
   |
15 | #![feature(core_intrinsics, convert)]
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

For more information about this error, try `rustc --explain E0554`.
error: could not compile `screenshot` due to previous error

Feature attributes are only allowed on the nightly release channel. Stable or
beta compilers will not comply.

Erroneous code example:
#![feature(lang_items)] // error: `#![feature]` may not be used on the
                        //        stable release channel

If you need the feature, make sure to use a nightly release of the compiler
(but be warned that the feature may be removed or altered in the future).