Hi! Do you mean I must click on that link https://upload.wikimedia.org/wikipedia/commons/thumb/9/9d/Deepwater_Horizon_offshore_drilling_unit_on_fire_2010.jpg/1280px-Deepwater_Horizon_offshore_drilling_unit_on_fire_2010.jpg?

So when I click on that link staying at google chrome, that returns me the following

It's really strange because though I have the kaspersky antivirus, firewall is on, but until recently it didn't bother me. Furthermore images were displayed in a some time. I tried to close the antivirus and others but it didn't work. But thank you, I thought this problem is in wikipedia site.

The way this normally works is that the antivirus installs itself as a root certificate authority (that can issue certificates for any domain) in the certificate store of your OS or browser, intercepts internet connections and does a man-in-the-middle attack on them (using a normal HTTPS connection between the website and the antivirus, and a HTTPS connection signed with its own certificate between the antivirus and the browser) so it can examine/filter web traffic. It looks like something went wrong with the first step (maybe an OS or browser update changed how the certificate store works? or something reset it?) and the browser does not accept the antivirus' authority to issue certificates for wikimedia.org anymore.

Although in that case I would expect seeing similar warnings for Wikipedia itself.

Thank you, I'll try to scan my PC for searching viruses, I think this is only way I can do.

Dear TGR, good day. I've installed the kaspersy secure connection. As I understand this programm supports some VPN. So as soon as I opened it I'm able to see the images. Do you know what that means? The problem appears only this site.

Probably that Kaspersky is intercepting your connection now and it does it in a non-broken way? You can inspect the certificates in your browser to verify. The old interception might be disabled because it was done by another antivirus which got disabled in the installation process, or it was done by some malware which is clever enough to deactivate when it detects an antivirus; or maybe whetever did that is still intercepting your traffic, but now you don't see it since Kaspersky is also intercepting it and that happens later in the process, so you get Kaspersky's certificate.

(Or something else entirely... I'm not exactly an expert. Someone from Traffic or Security-Team might have a better idea.

Good day, thank you for your advice. I don't know how or why but after checking my PC by ccleaner, kasperksy's utility, malwarebytes. Now everything is good. I'll try to message to security-team next time if the problem happens again. Thanks!