How are you inserting the picture in your page? are you explicitly defining the Width and height of the picture? If you are then it should display exactly at that size. For example, try something like this:
<p><img alt="test-pic" height="190" src="2012-09-14_0516.png" width="380"></p>
In the above code, I have inserted the width and height of the picture.
Also, avoid using spaces in the file name. for example insert hyphens or underscore like this:
"2012-09-14_0516.png"
I hope this gives you the idea.
