How to make an image responsive when displaying an image using php?

Question

PHP

Good evening! I am doing the output of news in wp and bootstrap and I want the previews to be adaptive. Here is the code:

<a href="<?php the_permalink(); ?>" title="<?php the_title(); ?>">
  <?php the_post_thumbnail();>
</a>

Specifying img tags in src="<?php the_post_thumbnail();>" does nothing. How should one act in such situations?

Answer 1

If this is WordPress + bootstrap, you can do this:

<a href="<?php the_permalink(); ?>" title="<?php the_title(); ?>">
  <?php the_post_thumbnail(null, array("class" => "img-responsive")) ;?>
</a>

Function documentation the_post_thumbnail, the second parameter is used to set attributes (including classes)

Answer 2

And here php?
Write CSS for different sizes.