How to Add Custom Image Sizes to WordPress Uploader

Written by Jean Galea
Written by Jean Galea
WordPress 3.3 is finally out, and features a host of new improvements in the UI, along with other novelties. A new feature I'm digging is the image_size_names_choose filter, which enables us to add new image sizes to the media upload/insert interface.

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See the updated and more complete post about image sizes in WordPress

WordPress 3.3 is finally out, and features a host of new improvements in the UI, along with other novelties.

A new feature I’m digging is the image_size_names_choose filter, which enables us to add new image sizes to the media upload/insert interface.

Check out the code below and the resulting screen:

if ( function_exists( 'add_image_size' ) ) {
add_image_size( 'new-size', 300, 100, true ); //(cropped)

add_filter('image_size_names_choose', 'my_image_sizes');
function my_image_sizes($sizes) {
$addsizes = array(
"new-size" => __( "New Size")
$newsizes = array_merge($sizes, $addsizes);
return $newsizes;



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Written by Jean Galea
Jean Galea is an investor, entrepreneur, and blogger. He is the founder of WP Mayor, the plugins WP RSS Aggregator and Spotlight, as well as the podcast. His personal blog can be found at

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35 Responses

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  4. Hello Jean! First I want to thank you for this post, it’s working perfectly but I just can’t figure out how you can add multiple sizes. I need two, for landscape and portrait pictures and now I have set it up only for the landscape ones,

  5. hello sir, how would you make so the size is width:100% and height is auto? thank you hope to hear from you soon

  6. hi
    I have put this code im my page. I want to apply this in plugins but I cannot select new size.
    what is the problem with this. any idea ??

  7. I have a problem:
    if (function_exists( ‘add_image_size’ ) ) {
    add_image_size(‘Imagen_slider’, 960, 400, true);
    add_image_size(‘Imagen_entrada’, 120, 120, true);
    add_image_size(‘Imagen_Item_Area’, 150, 95, true);
    add_filter(‘image_size_names_choose’, ‘size_mejorada_custom’);
    function size_mejorada_custom($sizes) {
    $addsizes = array(
    ‘Imagen_slider’ => __( ‘Versión grande para usarla en la portada’),
    ‘Imagen_entrada’ => __(‘Pequeña para los resúmenes.’),
    ‘Imagen_Item_Area’ => __(‘Icono para las entradas de Areas’)
    $newsizes = array_merge($sizes, $addsizes);
    return $newsizes;

    When i tried to upload a picture with size 117 * 115
    In the uploader i can select only

    Tamaño completo (117 × 115)
    Versión grande para usarla en la portada
    Pequeña para los resúmenes.
    Icono para las entradas de Areas (117 × 95)

    Only i can select: Tamaño completo and Icono para las entradas de Areas. But it have not my custom size,

    I use in the code:

    I think that i am using well the instructions.
    Thanks for your help

  8. I have a custom image size ‘slider’ defined. 950px X 300 px. In the wp_options table ‘slider_w’ = 950 and ‘slider_h’ = 300. When trying to insert an image to a post the size for ‘Slider’ is shown as 590×186. Any thoughts on why this may be happening?


  9. Hi,

    I tried but don´t work completely. I see the new size in the Media Edit but can select the new size and also doesn´ display the width and height, any idea ?


  10. I tried the code and it generates the image in the upload folder but i don’t see the new option in the media upload screen. I’m using 3.3.1 this would be really useful for my client to able to choose image size based on location rather than dimension ie ‘main post’, ‘recent post’

    many thanks


  11. This is fantastic, great article.
    One thing, is there a way to have these custom image sizes show up in the “edit image” editor as well? So if I go to edit the photo in the uploader, when I go to crop it and apply, it only shows the wordpress defaults.

  12. Hi.
    i have created my new image size 300 x 100 like your example but if i upload an image with the same width and height i’m not able to select New Size but only Full Size.
    Any help is appreciated!

    1. It should work as if it was a normal default wordpress size, so it should be usable in galleries too. There is also a great plugin called ‘Regenerate thumbnails’ which can be useful in combination with the code above.

  13. So, if the image was already uploaded, it seems to be KO, but if i upload a new image, it’s OK.

    Thx for your help, it will be usefull!

  14. Hi, Thx for the tip, but, it doesn’t work on my website.

    i pasted your code in my function file and when i want to insert a pic, i can see my new size without dimension, but i can’t select it…

    1. Try saving the post first and then see if you can select it. Or else try uploading one first image through the media gallery. It should work from then onwards. It just needs to be initialised that first time. Let me know if you still have problems after having tried that.

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