You can follow these 3 easy steps to customize the logo.
1. You can create a new "Custom HTML" module type from Module Manager in joomla back-end.
Add the below html code in "Custom output" field.
<div class="bt_fade_logo bt_fade_img"><a href="/index.php"></a></div>
Then, you have to publish the module at "logo" position.
2. Upload your logo in the folder: "/templates/bt_temlate_name/images/SKIN_NAME/joomla/" with name "logo.png".
3. Finally, open the file: "/templates/bt_temlate_name/css/joomla.css" or "/templates/bt_temlate_name/css/template.css", go to the line ~11-55 and edit the dimensions (width & height) of sprite* logo.
/* -------- Logo -------- */ div.bt_fade_logo.bt_fade_img { background-position: left top; background-repeat: no-repeat; width: 316px; height: 65px; position: relative; } div.bt_fade_logo.bt_fade_img a { background-position: left bottom; background-repeat: no-repeat; position: absolute; top: 0px; right: 0px; bottom: 0px; left: 0px; }