C++ library to convert JPEG and PNG images to RAW image format

I have tried searching for a day for converting JPEG & PNG to RAW image format(*.raw format), but couldn't find any and all the result were RAW to JPEG. Finally i decided to ask here hoping will get the answer.

So, i want to convert images of format JPEG & PNG to RAW image format(*.raw) only and for that i need C++ library which can do this work.

Please tell me some library for the same. Your help is highly appreciated.

Thanks