SMDH extracting large icon to bmp in c++

[Moocow9m]

I am trying to extract the large icon from a .smdh file but I don't know how I am supposed to write the file in bitmap format. I would also like the answer to be platform independent if possible. I currently have it loaded from the file into a char* called buff. I know this about the icon: size: 48x48 pixels, Most Likely encoded as RGB565, The data is encoded in tiles (starting from size 8x8, continuing recursively).
Below is an image of the raw data being output from the program read in notepad++ as it is now(just the image supposedly)

SMDH file type Source: https://www.3dbrew.org/wiki/SMDH