@endurion 

Thanks for pointing that out. It has since been fixed.  ?

@Shaarigan 

I have taken a  look at the links but it will take a while before I can make much sense of it as a whole. Currently I'm just modifying the program step by step to see how it affects the performance. Visibly nothing is different. Thanks for your input, I will read up on WM_PAINT…

Check out these…

10:15 - 26:00 - Casey Muratori - Endianness

https://youtu.be/0CB1mYS5wBc?t=615

Handmade Hero - Loading BMPs

https://www.youtube.com/watch?v=USFTH9mcaKw