Unusually, this tutorial starts in Photoshop. We need to build a specific kind of image before we start.

Make a nice frame. Note that there is a layer called “Color Fill 1”. Make this a solid color, and take a note of the HEX value of that color.

The image is then sliced, with the central portion being the most important.

Use Save for Web in Photoshop to save the central slice as a GIF or a JPEG image.

Save the Photoshop file too - you will need it later.