Hello
I was surfing at the net and then suddenly a new tab was opened and there was a picture.

Is this computer attack, or somebody attacked a web I was surfing in?

One of your already opened tabs could have done this with JavaScript. Though, I guess it's not the only possibility; a malicious program running in the background could have done it too.

To be on the safe side, I would suggest downloading Malwarebytes anti-malware. Just remember to update it before scanning.

Could be virus, could be anything. Hapenned for me once, but I solved it easily.