Twenty Ten theme logo in title problem

The problem is that when I try to insert logo image in the title of the page there is some strange black “border” around the image. I have tried it with a lot of images and error happens with every image, no matter if it is jpg,png transparent or not, also I have tried with border=”0″ commands but it looks like it has nothing to do with the border, maybe something to do with wrapper or I don’t know what.

Here is a picture so you can see exactly what I mean:
img

also here is the code I used to insert image to header:

<h1 id="site-title">
<span>
<a>" rel="home" title="<?php bloginfo('name');?>">
<img src="<?php echo bloginfo ('template_directory');?>/images/logo.png" alt="<?php bloginfo ('name');?>" />
</a>
</span>
</h1>
<!--end of h1 site-title-->

also I have tried some alternative ways of inserting image in that place with different code, I have tried like 3-4 options but I get the same issue every time.

If you can help me please explain things in the easiest way possible, because I am pretty much new to wordpress, css and html ??

Thanks in advance

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