HTC One Camera photos have "pink background"
It is not a software issue, it is a hardware issue. Most of the times, they are referred as pink spots or purple tint/haze

It happens because apparently the component called ZOE puts a lot of strain on the camera module, which causes it to heat, and it could even lead to burning down your motherboard (in extreme cases).

Reference: http://forums.androidcentral.com/htc-one/351874-htc-one-heres-skinny-infamous-purple-tint-thermal-defect.html

Better call HTC for a replacement/Fix before your Warranty runs out.