Issue to export images from rosbag file

I'm recording images from /camera/image_raw to rosbag file but when I want to extract them I get gray images with little squares like a grid on them:  I tried command line and launch file to record: rosbag record -O subset /camera/image_raw and launch file to extract the images but I get the same thing: I can visualize the images from the topic while they're publishing and I can see the RGB image correctly