Share image on a custom twitter share button

Question

Share image on a custom twitter share button

I have experience with facebook feed. I recently switched to using twitter and would like to create a custom share button on my website.

The problem is that I am linking to the photo cartogram tutorial, but the image is not showing,

it works when i use plain text

$('#twitter_share').click(function (e) {
    e.preventDefault();
    var loc = "<?= base_url(uri_string()); ?>";
    var title  = "<?= $video->title; ?>";

    window.open('http://twitter.com/share?url=' + loc + '&text=' + title + '&', 'twitterwindow', 'height=450, width=550, top='+($(window).height()/2 - 225) +', left='+$(window).width()/2 +', toolbar=0, location=0, menubar=0, directories=0, scrollbars=0');
});

but crashing when i share an image and i only need to share one image.

$('#twitter_share').click(function (e) {
    e.preventDefault();
    var loc = "<?= base_url(uri_string()); ?>";
    var title  = "<?= $video->title; ?>";
    var image  = "<?= isset($video->image_url) ? site_url("thumbnail/" . $video->image_url) : site_url("assets/img/cms/video.png"); ?>";

    window.open('http://twitter.com/share?card=photo&image=' + image + '&url=' + loc + '&title=' + title + '&', 'twitterwindow', 'height=450, width=550, top='+($(window).height()/2 - 225) +', left='+$(window).width()/2 +', toolbar=0, location=0, menubar=0, directories=0, scrollbars=0');
});