Add css style to first image inside wordpress post?

Question

css

There are many images in the post, all of them are displayed in full size. Unfortunately, all the images inside the post have the same css, and I only need to change the size and style (using css) of the first image in the post.
Can you please tell me if it is possible to add a certain css style (for example, first-image) for the first image inside the post through function.php or in some other way.

Answer 1

Nikita Ignatiev , thanks for the first-child hint :)
The solution turned out to be the following:
.entry-single p:first-child img {}

Answer 2

Perhaps the most time-consuming is to add a class for the desired picture in the post editor. And then in css change the styles of the class.