Wordpress: resize images - 128x128?

Question

WordPress

1. The first option (priority) - It is necessary to create copies of images not only in standard WP sizes, but also in custom ones, namely 128x128, 256x256.
How to do the same for existing records and make the new ones transform like that?
It is also necessary that the links come in single.php

2. If the first option is difficult, does WP have resize on the fly? (although I am not a fan of this solution)

Answer 1

Hello!

It is necessary to create copies of images not only in standard WP sizes, but also in custom ones, namely 128x128, 256x256.

https://wp-kama.ru/function/add_image_size
Register new sizes 128x128 and 256x256

How to do the same for existing records and make the new ones look like this?

And then, using this plugin, regenerate thumbnails for existing posts - https://ru.wordpress.org/plugins/regenerate-thumbnails/
If there are too many pictures and you have access to SSH, then look towards wp-cli

If the first option is tricky, does WP have resize on the go?

The first option is the easiest. Also not a supporter of resizing, I go