Image Upload in theme option page

Friends i need your help to solve an issue. I created a theme option page with multiple textboxes dropdowns etc. but I have no idea how to add an option to upload images such as logo. My code is simply a copy/paste from tutorals .. here it is.

array(  "name" => "Logo Image",
"desc" => "Insert Image you wish to display as logo",
"id" => $shortname."_imglogo",
"std" => CZR_THEME_URI . '/img/sample_logo.png',
'store'   => 'url',
'type'    => 'file',),

and the Render part is;

<?php } elseif ($value['type'] == "file") { ?>
<img src="<?php echo $value['std']; ?>" style="max-height:150px;" />
<input name="<?php echo $value['id']; ?>" id="<?php echo $value['id']; ?>" type="<?php echo $value['type']; ?>" value="<?php echo $value['std']; ?>" />

Friends kindly guide me how to upload the image and save its proper URL

Thanks