Is it permissible to work in a photo lab frequented by non-Muslims, where pictures are developed from their films that may contain what is Islamically impermissible, and is it permissible to continue in this job if its prohibition is confirmed until another job is found?

Photographing animate beings and earning from it is unlawful (haram), because if Allah prohibits something, He also prohibits its price. This is except in cases of necessity, such as identification photos and tracking criminals. The questioner can work by photographing inanimate objects or seek another profession.