is there a way to prevent other websites to load our resources in general or do I have to block any IP if I notice it?
Take your website offline is the only way. Once content is online it can be used, that’s the nature of the web.
Note you cannot use IP address to restrict as it’s the client IP address that would be sent to your server, if they just used an tag referencing your site.
Even if you did want to block based on referrer for example it would be easy to override (e.g. setting the
referrerpolicy attribute to
no-referrer in the tag), though admittedly many sites might not choose to do this so would would prevent basic reuse.
However the easiest way to get around it is to just download it and upload a copy to their site. You can not prevent this if your content is on the public internet. OK that’s better in some ways as no longer wasting your bandwidth, but also gives less visibility and still loses your content at the end of the day.
It’s a losing game - you’ll spend more time going round in circles chasing this. Accept this is the nature of the web and add copyright text and/or a source attribute to your images if really worried about it.