Learn how to make an image that can repeat in all directions in Photoshop 7.0 or later. Tiling images are great for desktops.
Step 1: Get a Good Picture
The picture you use should make sense when tiled (for example, tiles). A good example of a bad tiling image is one of a street sign, since you only need one. I used a nice picture of Bacon. You can find a good picture on Google, or you can just use my bacon.
Step 2: Open the picture
Open the picture in Photoshop, or GIMP. I will be using Photoshop 7.0. If using the bacon picture, for inspiration, go make bacon. After making the bacon, stare at it for a while, and eat it before it gets cold.
Step 3: Offsetting the image
Since the offset filter doesn't have a "half-image offset" button, we have to find out what half of the pixels of the image are. There are two ways.
1. Go to the "Image" drop-down, and click "Canvas Size". From there, make both of the drop-downs show "percent", and then change the percent to 50. Then, change the drop-downs back to "pixels" and remember the numbers.
2. Go to the "Image" drop-down, and click "Canvas Size". Calculate half of the canvas sizes, and remember the numbers.
Our bacon image is to be offset 190 x 127 pixels.
To offset, go to "Filter", "Other", "Offset..."
Make sure you select "Wrap Around"
P.S. Sometimes, if you have been working on the picture beforehand, make sure to crop the image, and select to delete the cropped out part. This gets rid of any unwanted offsetting.