Tilen breaks up your large images into smaller pieces for your web projects. The program takes an input image in many formats and breaks it up into as many pieces as you tell it to. The tiles come out in the format you specify and can be processed further with other programs.
You know how easier it is to download many smaller files than one large file. So if you are working on a website design that has a large image anywhere on the page, you might want to consider breaking it up in a few smaller ones. The user of that site will see that something is loading and won't try to reload or leave your page dissatisfied.
The program's interface is very simplistic. There is your image in the center. In the title bar, you get to see its name and its dimensions. Below the picture there are controls for the number of tiles the picture is going to be split up into. The program helps to see your original image dimensions as you can just use a calculator to split the picture into even-sized tiles.
You can set the extension and the location for the output files. You can later add some effects to each one of them - allowing you to create a diverse and different look for your site. This tool comes free of charge and can be very handy indeed.