Compare visual stimulation on a screen and through a VR headset

Dear Users,
I would like to use a VR headset to present still images to participants. We succeded in presenting still images through the dedicated software (Steam VR) which applies processing to images so that they can be viewed easily in the headset. I wondered if you were waware of any solution to keep theses processings making still images usable through VR headeset but allowing to use the headset as a simple video output such as a monitor.
Maybe someone has already tried to build experimental runs that directly compare vision on a simple screen and through such a headset ?
Thank you very much for your help,
Best regards,
Harold