Resizing images in Redactor

I've upgraded to the Redactor II plugin for creating blog posts but can't work out how to enable it to resize images. I've updated the _config.inc file to enable the setting for both imageResizable and imagePosition but this doesn't seem to do anything. Does anyone know how to enable this feature?

Here's my updated _config.inc

<script type="text/javascript" src="PERCH_LOGINPATH/addons/plugins/editors/redactor/redactor.min.js?v=1.2.5"></script>
<link rel="stylesheet" href="PERCH_LOGINPATH/addons/plugins/editors/redactor/perch/edit.css?v=1.2.5" type="text/css" />
<link rel="stylesheet" href="PERCH_LOGINPATH/addons/plugins/editors/redactor/redactor.min.css?v=1.2.5" type="text/css" />

<!-- Plugins -->
<script type="text/javascript" src="PERCH_LOGINPATH/addons/plugins/editors/redactor/plugins/source.js"></script>
<script type="text/javascript" src="PERCH_LOGINPATH/addons/plugins/editors/redactor/plugins/video.js"></script>

<script type="text/javascript" charset="utf-8">
$(function() {
    var set_up_redactor = function() {
        $('textarea.redactor:not([data-init])').each(function(i,o){
            var self = $(o);
            var uploadFields = {
                    'width'  :  self.attr('data-width')||'',
                    'height' :  self.attr('data-height')||'',
                    'crop'   :  self.attr('data-crop')||'',
                    'quality':  self.attr('data-quality')||'',
                    'sharpen':  self.attr('data-sharpen')||'',
                    'density':  self.attr('data-density')||'',
                    'bucket' :  self.attr('data-bucket')||'default'

                };
            self.wrap('<div class="editor-wrap" style="float:left;"></div>');
            self.redactor({
                imageUpload: 'PERCH_LOGINPATH/addons/plugins/editors/redactor/perch/upload.php?filetype=image',
                fileUpload: 'PERCH_LOGINPATH/addons/plugins/editors/redactor/perch/upload.php',
                fileUploadFields: uploadFields,
                imageUploadFields: uploadFields,
                imageResizable: true,
                imagePosition: true,
                plugins: ['source', 'video'] // Plugins
            });
            self.attr('data-init', true);
        });
    };

    set_up_redactor();

    $(window).on('Perch_Init_Editors', function(){
        set_up_redactor();
    });

});
</script>