Open your selected tube, either
pick two contrasting colors with your eyedropper tool
to
make a gradient, or use a ready made gradient from your materials
box.
Flood Fill
your
transparent image with your chosen gradient.
Effects/Plugins/Simple/Diamonds
Effects/Distortion Effects/Pixelate.
Settings at 15.
Activate your tube.
Edit/copy
Edit/paste as a new selection on
to your gradient filled background image.
Move in to desired position.
Effects/Drop Shadow.
Layers/Merge/Merge all
flatten
Add your watermark and Save as a
JPG image to be assembled in Letter Creator.
**Note: In Letter Creator, I did
not tile the image, but rather let the text scroll.