I have looked for an answer with no sucess.
In my 18.104.22.168 Magento I can upload a QR code png image, dimensions 164 x 164, size 400 bytes, it shows fine in the admin area, but will not display in front end (just shows "Loading" forever...).
I have tried different images from the QR code generator, all almost identical size, all fail on frontend. They do work if I convert them to GIF.
The original Png files DO work on my 1.9 Magento installation (on the same server).
Can anyone suggest why that might be, and how I can fix this?