How to display square thumbnails in Wordpress?

Question

WordPress

There is a task - all thumbnails should be exactly square and arranged in 3 columns. But how to do this if the images have different sizes?
Here is an example

Answer 1

well, this is already css , it’s quite simple:
1) specify a static width and height for images
2) well, remove the border-radius from the img and / or from the block in which the img is located (it may still contain overflow:hidden;)