var custom_uploader;

$('.upload_image_button').click(function(e) {
    input = $(this);
    e.preventDefault();

    custom_uploader = wp.media.frames.file_frame = wp.media({
        title: 'Choose Collage Image',library: {
            type: 'image'
        },button: {
            text: 'Choose Collage Image'
        },multiple: false,displaySettings: true,displayUserSettings: false
    });

    custom_uploader.on('select',function() {
        attachment = custom_uploader.state().get('selection').first().toJSON();
        input.prev('input').val(attachment.url);
    });

    custom_uploader.open();

});

这很完美.
我添加了两个与我的插件完全相同的图像大小：

if ( function_exists( 'add_image_size' ) ) {
    add_image_size( 'collage-large',460,660,true );
    add_image_size( 'collage-small',325,true );
}

我的问题：
媒体上传表单中未显示图像大小的选择器或更好的缩略图选择器.我怎么做？