Icons on sidebar will not align

Hi,

I have tried to place 3 social media icons on my sidebar at https://www.relasjonerognettverk.no. Two of them has aligned in a line as I want them to, but the last one is placed all wrong. All Icons are 64×54 px but as you can see the Twitter icon looks smaller.

This is the code that I have used:

<a href="https://www.linkedin.com/e/fpf/17684837">
<img src="https://www.relasjonerognettverk.no/wp-content/themes/convergence/images/linkedin-button1.png" class="fl" />
</a>
<a href="https://www.facebook.com/pages/manage/?act=38004305#!/pages/Relasjoner-Og-Nettverk/108075015914530">
<img src="https://www.relasjonerognettverk.no/wp-content/themes/convergence/images/facebook_button.gif" class="fl"/>
</a>
<a href="https://twitter.com/#!/Sturla_Lang">
<img src="https://www.relasjonerognettverk.no/wp-content/themes/convergence/images/twitter_icon.png" />
</a>
<div class="fix"></div>

What have I done wrong? I want all 3 Icons on a line.