copyright of pictures / digital signature

I am hoping to get an answer to a scenario. I have downloaded few images using Google, then clicked on the "properties" option, here, i see some of it showing details when was taken etc, and copyright by (© name of person or © getty images) however lots of images are comes up with no details at all. Does it mean if you cannot find info who is it belongs to (i call it digital fingerprint) i can use it? how can i contact with owner to get permission to use it if i cannot find who is belongs to??

Thanks Kristina