how to find alternate url

hi all,
i have a minor problem because i'm not very good at php
let say that i'm running a webcam for my office.
today i came to my office and start my computer, at the computer installed a webcam that every 5 second capture the picture of me and saving the file to some folder and file, let say that the folder called webimages at somedomain.com and the filename called images.jpg. so, to view the image we go to this url http://somedomain.com/webimages/images.jpg.

the problem is when i turn my computer the link will go down (i have to turn off the computer)

how to make some script to show another url if the link is down

some thing like this

<img src="http://somedomain.com/webimages/images.jpg" />

i turn off the computer and the link will go down
after the computer is off i want the link to show to other url
like

<img src="http://otherdomain.com/blankimages.jpg" />

how to do this is PHP?

thank you

 

Use PHP's fsockopen function to see if a specific server responds:

@$fp = fsockopen ( $domain, $ports[$portNames[$y]], $errNum, $errMsg, $timeout);
if (!$fp) {
	// server did not respond
	// add whatever code you want to run in this case
} else {
	fclose($fp);
	// server DID respond
	// add whatever code you want to run in this case
}

Code (markup):

The @ prevents an fatal error from being displayed on your page. The fclose() is just to disconnect for neatness's sake

 

whoa, i still dont understand......
i'm sorry for my incapability.

 

ini_set (default_socket_timeout, "3");
error_reporting(0);
$theurl="http://somedomain.com/webimages/images.jpg";
$filestring=file_get_contents("$theurl") ;
if($filestring){
  echo"$filestring";
}
else{
echo"http://somedomain.com/alternateimage.jpg
}

PHP:

 

Thank you mad4, its working...

 

Oh, my mistake... I thought you wanted to serve an image from an alternate server that's what my code does.