I got stuck there too - got it to work by opening QR code in the app on my phone (the app wouldn't allow screenshots), pulled the top menu down a bit to dim the screen as it goes very bright, then took a picture with my tablet, cropped it with a mm or two around the edge (it was slightly wonky as well), then used those pictures and they were accepted by Thailand Pass and application accepted within a couple of minutes. Also if anyone has any long documents - print pdf to pdf viewer and do 'fit on one page' then convert to jpg or png.
