Why do so:
I'm talking about the numbers after the format.
To make the browser think that this is another photo and reload it, not from the cache.
Actually happens, for example, for captcha. In general, there are many different reasons.
One of them is to see where the URL is requested from, for example, if you repeatedly request a picture with one number, it means they throw a direct link to it, but you have to force people to go through the site and see the advertisement