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I'm tearing my hair trying to get additional image sizes appear in the media section when i upload new pictures. It works on older versions of wordpress but i can't get it to work on v 3.5.2

Here's my code in the functions.php file and i'm using the underscores.me framework to build the theme.

    Custom image sizes

add_action('after_setup_theme', 'images_setup');

function images_setup() {


    if (function_exists('add_image_size')) {
        add_image_size('slider', 1170, 400, true);
    // Getting these sizes to appear in the media section within wordpress
    add_filter('image_size_names_choose', 'my_custom_image_sizes');

    function my_custom_image_sizes($sizes) {
        $custom_sizes = array(
            //'custom-post-thumbnail' => 'Custom Post Thumbnail',
            'slider' => 'Slider'

        return array_merge($sizes, $custom_sizes);

share|improve this question
Have you seen and tried the solutions from this thread? – toscho Jun 24 '13 at 5:42
I'll check it out but i certainly don't want to use a plugin to achieve it. Thanks tischo :) – arkhamDev Jun 24 '13 at 6:01
Tried it out, still not working :) – arkhamDev Jun 24 '13 at 6:12
With the code in place, try uploading another image, and make sure it's bigger than 1170 x 400. If that solves nothing, we've got a mystery (because I just tried your code in 3.5.2 & it works perfectly!). – TheDeadMedic Jun 24 '13 at 6:47

I'm running WordPress 3.5.2. The following is an excerpt from my functions.php file, which correctly allows me to select a thumbnail size when I upload an image.

// Basic setup for thumbnail support.
function themeSetup()

    add_image_size('tiny', 128, 79);
    add_image_size('small', 256, 158);
    add_image_size('medium', 384, 237);
    add_image_size('large', 512, 316);
add_action('after_setup_theme', 'themeSetup');

// Addes custom sizes to Media Library.
function addMySizes($defaultSizes)
    $mySizes = array
        'tiny' => 'Tiny',
        'small' => 'Small',
        'medium' => 'Medium',
        'large' => 'Large'

    return array_merge($defaultSizes, $mySizes);
add_filter('image_size_names_choose', 'addMySizes');

As you'll notice, we have pretty similar answers. I'm not a PHP expert, but those nested functions give me the willies. I would unnest them and see if that fixes your code. Maybe it's just a timing issue, i.e. your call to add_filter() is too early.

If this doesn't fix the problem, then it's probably something else. Try deactivating all your plugins, etc, standard WordPress debug procedure.

share|improve this answer
Thank you :) all i did was added the tiny, small, medium and large sizes and moved my add_filter below the function that adds my sizes and it worked. – arkhamDev Jul 7 '13 at 4:50

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