Does including images is always necessary when it comes to doing content marketing?
The fact here is that if you include an image that helps the visitors to understand the content easily for example by an inforgraph. Then its always preferable to include it. But its not completely necessary. Content without images can also do well.
Images are always good for user experience. And also they can rank separately so its a win win if you did. But no one can say that they are necessary.
Its not necessary but its good for your site if you can include them.