Icon too small

Hello, I started to create a prototype to show my supervisor, and really wanted to make the application look similar to the existing product we use.  I love the CSS generator, and used the logo to create a new theme.
My problem is, when I place the logo in the Common/Header, it is too small.
I tried to make the container larger, or just plain paste the image, but cannot seem to control the size that it shows up in the header.
Please advise.
Increase the max-height from the Application_Title class:

.Application_Title img {
    max-height: 20px;
    padding-bottom: 4px;
Great, thank you!!