This post has been marked by the post author as the answer.
for anyone else having this issue Preben posted on the GitHub:
Quote: "Hi GraphiX
ahh i see thats a easy one
, the png need to be in 32 bit format , in the code - Decompress/Copy from a 24b to our texture_d 32b will not work.
So just load your png and save as 32 bit."
just tested and can confirm this works saving the .png as 32bit - strange thing is it use to work in the DX9 as 24 bit so it must have changed at some point
Welcome to the real world!
Main PC - Windows 10 Pro x64 - Core i7-7700K @4.2GHz - 32GB DDR4 RAM - GeForce GTX 1060-6G 6GB - 1TB NVe SSD
Test PC - Windows 10 Pro x64 - G4400 @3.3GHz - 16GB DDR3 RAM - GeForce GTX 950 2GB - 500GB SSD