Example: <?php $logoId = mt_rand(1,5);?>

Note: I’ve been informed that in php < 4.2.0, mt_rand() must be seeded manually. An easy way to do this is to add this line before your mt_rand() call.

<?php mt_srand((double) microtime() * 1000000); ?>

Once you have a variable ($logoId in this example) containing your random integer, you can use that in the file name specified by the source property of your image tag.

Example: <img src=”/images/logo_v<?php echo $logoId;?>.jpg” alt=”alt text”/>

In this example, if $logoId is 4 then the image source will be /images/logo_v4.jpg. Likewise, if $logoId is 2 then the images source will be /images/logo_v2.jpg. This is a very easy way to have a random image. Once you have those two lines of code, you just have to make sure your image files exist and you’re done. If you wanted to have six images instead of five, you would just change the 5 in mt_rand() to a 6 and add the appropriate image file to your images folder.