I downloaded 3 QR codes, they are png files. When I import them into CorelDraw or try to open them in PhotoPaint they are just a black squares. However, when I look at them with any photo viewing programs they are proper looking QR codes. Anyone have any idea what is going on? I have attached one of them.
I just opened this one that you posted, in PP and it was correct. I viewed the image in Waterfox (64 bit Firefox) and then copied and pasted that image in PP. More than likely, these QR codes are not valid png files, or they may have some header data screwed up, somewhere.
You may want to use something like IrFanView to open it and then re-save it, then bring it into DRAW or PP.