Can I use a dark or dim room photo?

You can, but the preview quality will be lower than with a well-lit photo. The AI uses shadow and light-direction information from the room photo to blend the placed furniture realistically into the scene. In a dark photo those cues are reduced, which means the furniture may not match the lighting environment as accurately and can look less convincingly integrated.

The practical fix is to take the photo during the day with as much natural light as possible. Opening blinds or curtains before shooting can significantly increase the light level in the photo without any equipment. Natural light that enters from a window gives the AI useful directional shadow information to work with.

If your room has no windows or genuinely has very limited natural light, turning on every available light source before shooting will help. Even a modest improvement in how much light appears in the photo produces a noticeably better furniture placement result.

DecorViz works with any photo, but a well-lit shot gives you the most realistic and useful preview. A quick retake in better light is always worth it. Try it free on your own photo.