I'm having an issue zooming large png/jpgs with the built in viewer,
basically zooming images above a few megabytes in size has abnormal behavior.
A 20mb png can zoom to 400%, but going to 800% causes the image to return to 100% zoom (while the status bar reads 800%)
A 80mb png zoomed to 150% and the entire image turns black, zooming to 200% the image is still black, zoom to 400% and the image returns at 100% zoom (with status bar reading 400%)
A 292mb png can zoom to 150%, but subsequent zoom levels all show the image at 100%
Have uploaded an 87mb png here in-case you don't have one handy
All these files zoom in GIMP and the Windows photo viewer (system has atleast 20gig of ram free, so thats not the issue either)