Why can the thumbnail disappear when sharing a VKontakte page?

Question

JavaScript

Hello!
The problem is this: I screw the ability to rummage through the VKontakte page. The peculiarity is that when working on the page of the domain example1.com , we are trying to fumble the page of the domain example2.com.
If you implement sharing by connecting external JS provided by VKontakte, then everything is in order. But for a number of reasons, this method is not suitable and I want to use vk.com/share.php . Moreover, according to the documentation, if the page that we are fumbling has a domain different from the current one, you need to specify the title, description and thumbnail manually. All this is indicated with the help of the appropriate attributes, the preview of my entry also looks the way it should.
After clicking on the publish button, the title and description remain, but the thumbnail disappears somewhere. Can you suggest what could be the issue?
I tried the goodshare.js library, I thought it would help - there is the same story :(

Answer 1

In general, I figured out this problem. Suddenly it will help someone in the future: if the link to the image does not have a file extension ( example.com/img/myimage) , then VK will not embed the image. So the correct link should be like this: example.com/img/myimage.png

Answer 2

There can be at least 2 options:
Try reducing the xy size, and add at the end of the image .../img.png?123for example.