It's not difficult. Open the file in Photoshop. Crop it so that it is square and note the pixel dimensions. Let's say you now have an image which is 60 x 60 pixels. Now choose Filter>Other>Offset. Put half your pixel dimension in both Horizontal [ ] pixels right and Vertical [ ] pixels down boxes (so in this case 30 in each box. Make sure the Wrap Around button is checked and click OK. Your image will now have a horizontal and vertical line where it has been offset. Using the clone tool carefully work over these lines so that they disappear, being careful not to go off to the edge of your image (it's important not to change the edge pixels). When you've done you can test your tile by selecting it (Ctrl+A), choose Edit>Define Pattern. Open a New document (Ctrl+N) and make sure the pixel dimensions are much bigger than your pattern (such as 600 x 600 pixels). Then choose Edit>Fill and select Pattern from the Contents Use drop down. Click OK and admire your work. HTH Mark