How to Make an Easy Stationery Background Like This One!
Using Jasc Paint Shop Pro v. 7 and a graphic of your own

In PSP, use File - Browse to find a pretty picture and open it. This castle is a screen capture from my daughter's Cinderella Castle Designer game, which was what happened to be open on the computer when I came to it to start this project :-)
Select the part of the picture that you want to use for stationery by using the Selection tool. Once the good part is selected, click Edit - Copy.

Close the original without saving changes. Select Edit - Paste - As New Image.
Resize the graphic as necessary so that it's a good size to be on a stationery, perhaps 150 pixels on the widest edge. Use Image - Resize and enter just one dimension into one of the pixels boxes. Maintain Aspect Ratio should be checked, and the other dimension will go in automatically.

Part 1 - Adding Borders to the Graphic
Click in the right-hand Style box to change the Background color to black. (Active color is on the left, Background color is on the right.)

Go to Image - Add Border and add a black border one pixel wide. This is so that the next selection operation won't accidentally get part of the image in with it. Make sure Symmetric is checked.

Click OK
Now select the Eyedropper tool.

Choose two colors from your graphic. Right-click on one color and left-click on a contrasting color. These will be the theme colors of the stationery.
Go to Image - Add Border and add a five pixel wide border.

Click OK
Click the arrow between the two active colors to switch background to foreground. (Either of those double-pointed arrows does the same thing.)

Then click Image - Add Borders again and add another one in the contrasting color. (You can make the second border seven pixels wide for more drama. It's only five pixels wide in this illustration.)
Result should be something like this:

Click the magic wand and select the outer border. Now there should be marching ants around the border.

Go to Effects - Reflection Effects - Kaleidoscope.

Use whatever settings are in there and click OK. If you don't like the results, click Edit - Undo and come back and try different settings.
While the selection is still on the outer border, now click Effects - 3D Effects - Outer Bevel. Make the Width 1 (or it can be set to 2 for more dramatic effect)
Remember, in any of these Effects dialog boxes, be sure to click the preview window and move the hand around until it's showing the portion you have selected, and click the Zoom In button until you get close enough to really see what's happening.

Click OK on that.
Now use the magic wand to select the inner border and apply Outer Bevel to this border also, via Effects - 3D Effects - Outer Bevel.
Results so far:

You might want to save a copy of your graphic at this point just for safety's sake.
Step 2 - Making the Seamless Background
Make sure there is no selection by clicking Selections - Select None.
Make a duplicate of your image at this point by clicking Edit - Copy and then click Edit - Paste - As New Image. Now there are two pictures exactly the same. One is going to stay the way it is and one will become the background pattern.
Click Effects - Reflection Effects - Pattern. Play with the boxes until the effect is something you like, but be SURE the Scale Factor box reads 0, otherwise the background won't tile correctly.

Click OK.
Click the mouse inside the Foreground color in the Styles box and hold it down for a moment until the menu opens up from which you can click the box with nine little dots inside to select Pattern.

Once the pattern appears, click it once to open the Pattern selection box.

Click the pattern that appears to bring up the box from which you can select any pattern. Scroll up to the very top to find the temporary patterns based on the windows that you currently have open, including the pattern you just created. Click on the pattern you just made.
Make SURE the Scale is 100% and the Angle is 0.

Click OK.
Now you need to find out the exact measurement of your square, bordered graphic. Click on it to make it active, then click Image - Image Information to find the dimensions. The second number is the height and that's the one you need to know. Here mine is 172.

Now open a new image using File - New. Make the new image 1024 pixels long and the same height as your graphic. (It's 1024 pixels long because that's the most standard screen pixel measurement and should display correctly on most people's email programs.)

Click OK.
Select the Flood Fill Tool (the little bucket) and click inside the new image. It should fill with the pattern.

Now click Layers - New Raster Layer. The Layer Properties box comes up. Click OK on it.
Click the Flood Fill Tool (the bucket) and RIGHT click inside the image to flood it with the plain Background color.
Then click on the Layer Palette. (Your layers will be called Layer 1 and Layer 2, I renamed mine just for illustration.) Grab the Layer Opacity slider and move it down until you can see the patterned background through the plain color, but it's still light enough to be able to read email text over. Don't make it too hard on people's eyes!

Now go back to the finished, bordered graphic and click to make it active. Then copy it by clicking Edit - Copy.

Click the rectangular stationery background and click Edit - Paste - As New Layer. It will appear in the middle like this.

Grab the graphic and slide it over to the left. Click View - Zoom In a couple times so you can see exactly what you're doing. Be sure you've scrolled all the way to the left! Line the graphic up exactly on top, bottom and left sides.

When you zoom out, it should look like this:
Click File - Export - JPEG Optimizer. Set the compression value to 20. Give the graphic a memorable name and that's it, you're done! Now you can use it for email stationery.