Before anything you are going to need your icon set ready on your hard drive to upload to your website. You do not have to create the images yourself, google free icons, you will find there are a lot of sites providing them. https://www.iconfinder.com and http://www.iconarchive.com are both okay sites that don't freeze my browser with a ton of ads. Both sites also provide 48x48px images which is perfect for click images. The max your images should be is 50x50px.
When downloading you will get a prompt about where to download the image on your hard drive. During this step is a good time to name the images a through i (all lowercase) as the script requires this to be their names.
There are nine images in every default set, your custom set also needs to contain nine images total, no less, no more. The file extension does not have to be png, they can be jpg or gif images, however they must all be the same extension in any single set. Have you downloaded all nine? Okay, next step.
To begin create a folder (http://auroracoderz.info/index.php?topic=48.0) in the folder named clickimages.
Next go to a default image set and copy over the index.php file, you can copy a file by selecting it, holding the Ctrl key on your keyboard and dragging it to the new folder.
Now it's time to upload your custom click images to the folder you just created. As you can see above they are all named letters in consecutive order from a to i, your images should be named the same.
In admin go to Site Functions > Site Settings > Site Settings and then the Click tab. Here is where you choose the new click image set from the drop down where it says choose click image set, below that choose the file extension you have decided to use in image extension type (png, jpg, or gif). If you need to change the timer bar background and text colors to match your new image set this would be the time to do that. Click save... you don't see your settings save? Reload the page, it's a server software issue we have no control over. You should now see your nine images with your timer and text colors. If the images show as broken you have either not named them a through i or you have chosen the wrong extension type. Check those two things.