Is there a way to scale up post thumbnails on Wordpress?

On a featured div I want a post thumbnail/featured image with 584×348 px. When I upload a smaller image as a featured image on a post, it won’t scale up to this size. If the image is 250×250, it will appear 250×250. But if I use a larger image as featured image on the post, it will resize normally.

The thumbnail in functions.php is set this way:

// This theme uses post thumbnails
add_theme_support( 'post-thumbnails' );
set_post_thumbnail_size(150, 150); //size of thumbs
add_image_size( 'post-thumb', 600, 380, true ); 

The div:

<div class="featured_thumb"><?php if ( has_post_thumbnail() ) { the_post_thumbnail( 'post-thumb' ); } ?></div>

And the class:

.featured_thumb {background:#0C6; width:584px; height:350px; overflow:hidden;}

Can someone help me to figure out how to do it please? I thought of using timthumb but I’ve seen lots of complains about security. Not quite sure about it… Anyway, hoping someone could help me.

  • WordPress's image handling has checks built in that specifically prevent it from scaling images upwards like this, because they look terrible. There is no way to do this without custom code around large parts of the image system.
    – Otto
    Commented Mar 24, 2013 at 12:44

2 Answers 2


As WordPress thumbnail generator doesn't do this "scale up" thing, you can do it using the following CSS rule:

.featured_thumb img{ width:100%; height: 100%; }

Hope it will help.

  • This actually worked. Thank you. Something so simple I hadn't tried. Commented Mar 23, 2013 at 18:52
  • 1
    Please dont forget to select an answer as the selected answer when it solves your problem in StackExchange. That way it encourage the person who takes time to answer your question. Thanks and glad that it helped. Commented Mar 23, 2013 at 18:56

If You upload small dimension image and want that image in greater dimensions then image will be Blur.

So upload max dimesion image and scale it upto small dimension so image will not be blur.

  • I thought that, but the thing is that the people who would be posting are not into these stuff. This would be an easy way for them, even if it means the image would blur. Thank you, anyway. Commented Mar 23, 2013 at 18:52

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