How to dynamically display the image from which the Wordpress thumbnail is generated?

Question

Images

Hello.
When adding an image to the library, it is cropped to a certain size using a plugin (tinypng) and the original is overwritten. From this picture, a miniature with a smaller size is obtained.
Question: how to display the original picture ( from which the thumbnail is obtained ) dynamically ( not by ID )? Or how to get the ID of the desired image for further work automatically?
The picture must be displayed on the post page and without using the editor.
I think you should use <?php echo wp_get_attachment_image( ); ?>, but only the thumbnail is captured here.
To make it even clearer: the effect should be exactly the same as if I inserted a picture from the media library in the post editor.

Answer 1

Hello.
In the case of the wp_get_attachment_image function, you can specify the size as the second parameter. The original is full.
If this is a post or page image, then the the_post_thubmnail or the_post_thumbnail_url functions can be used.

<?php the_post_thumbnail('full'); ?>

<img src="<?php the_post_thumbnail_url('full'); ?>" alt="">