Viewing Tile able Textures in Photoshop

Ever wondered how to view textures you have just made a tile able texture in Photoshop? here is how you do it taken from "3D Game Textures, Second Edition" just follow the instructions.

Testing a Tiling Texture In Photoshop

After you have rebuilt and repaired the texture to your liking, you
can test the tiling of the texture. This is easy to do using the Define
Pattern option in Photoshop. Note that there is a difference between
defining a pattern and the Pattern Maker. We are defining a pattern
to later fill in an area; this does not alter the image. Pattern Maker
attempts to create a tiling pattern using a selection. Pattern Maker
gives me mixed results, sometimes good and sometimes bad. Even
the good results will require some touchup.
1. In order to get the best result, you may want to first look at
your image size. If you are working on a large image (and you
should be), you might want to create a copy of the image and
reduce it to 256×256 so you can tile it across a larger canvas
without creating a super huge image.
2. Select your entire image (Ctrl+A). You can select an unflattened
Photoshop file, and this method will create a pattern using all
layers that are visible.
3. Go to Edit > Define Pattern. These steps are illustrated in
Figure 4-38.
4. The Pattern Name dialog box will appear and you will see a
small thumbnail image of your pattern and have the option to
name it.
5. Select OK. Nothing will seem to happen, but your pattern is now
in the Pattern Preset Library.
6. Create a new image (Ctrl+N) and make it at least four times the
size of your texture. If your image is 256×256, then make the
new image at least 1024×1024.
7. Select the entire surface of the new image (Ctrl+A).
8. Right mouse click inside the selection and choose Fill.
9. When the Fill dialog box comes up, you will be able to choose
what to use to fill the selection with.

3D Game Textures, Second Edition- Create Professional Game Art Using Photoshop[Team Nanban]tmrg