do rviz need urdf file for viewing camera feed?

edit

The Image display shows a raw image, without aligning it to any of the other sensor data in rviz, so it doesn't require any of the tf frames to be correct.

The Camera display shows the image data overlaid with the other data that is visible in rviz, which means that it requires the tf transformations from your fixed_frame to the frame listed in the image message header to be correct. (If you check the terminal where you ran rviz, you will likely see TF errors informing you about this).

If you don't have any other sensors or tf frames set up, you can set your fixed_frame to be the same as your camera frame, and then you should be able to see an image in the Camera view.

(Setting up TF is a topic unto itself. You can use a URDF and robot_state_publisher to publish the TF tree for your robot, or you can use the TF static transform publisher for simpler robots)