Static frame instead of video feed?

Hi, We are using ARToolkit in an Android AR student project and are looking forward to use QCAR instead because of its great performance and functionnalities. We would like to use QCAR's Multi-target Tracking on a pre-taken picture (a static frame) instead of using the device's live camera feed. Playing around with the MultiTargets sample, I noticed the QCAR::Renderer uses a QCAR:State which contains the current frame of the camera device. Would it be possible to impose an existing frame (stored, for instance, on the device's storage) to the Renderer? I'm having a hard time thinking of an implementation since the camera device seems to be controled strictly on the native side. Thanks!