I am running firmware version 1.1.5 on the Ubiquiti (UBNT) AirCam.
First open an ssh session to the AirCam using putty or another ssh client.
Login using the username and password.
Enter the following line:
mkdir /etc/persistent/www ; ln -s /tmp/snap.jpeg /etc/persistent/www/logo.gif ; save
The image should display.
Here is the code I am using for the web page
<div id="AirCam" class="LiveImg">
<img src="http://192.168.1.63/images/logo.gif" alt="" class="photo">
</div>
<script type="text/javascript">
setInterval(function(){
$("#AirCam img").attr("src", "http://192.168.1.63/images/logo.gif?timestamp=" + new Date().getTime());
},30000);
</script>
Another option is on the UBNT forums: