One thing that i found is to use compressed_image_transport pkg. By using that you can republish compressed image to another topic with that launch command:

rosrun image_transport republish raw in:=/usb_cam/image_raw compressed out:=/usb_cam/image_compressed

or you can manually do it in the node.

This improve FPS significantly and at least in my case it stopped lagging. However, it would be nice to hear ant other solutions.