What is this code doing?

[bulliedog]

I have the following code on my reply and start new topic screens.  It obviously results in a blank button, but what what is it dong there?  I am using SMF Beta 5.

Code Select Expand

<img src="http://www.mysite.com/forum/Themes/default/images/blank.gif" alt="" id="fetchSessionTemp" />


Edited to add:
The button appears right next to the Post and Preview buttons.

[Grudge]

It is a cunning way of keeping your session alive. Every so often javascript changes the src of that image to a keep alive php script that attempts to keep your session going. If you remove it you will get more timeouts.

[bulliedog]

I get it now...thanks Grudge.  I guess my problem is that I over-wrote the truely blank.gif with a blank button.

*sigh*