How to Create Clouds in Photoshop CS6
The Clouds filter in Photoshop CS6 can muster a sky full of clouds from scratch with a few clicks of the mouse. This filter creates clouds using random values from the foreground and background colors. Indeed, most Photoshop veterans use this filter so much that they have a surprising number of clouds in their images.
Find it at Filter→Render→Clouds. To create a more contrasty cloud effect, hold down Alt (Option on the Mac) quickly when choosing the command.
If you don’t like the first set of clouds you get, apply the filter again and again until you do. If you want a more “realistic” sky, try using a dark sky blue for your foreground color and a very light blue, or white, color for your background color.
You can also use this filter with a solid colored square image to create a quick textured background. Be sure to apply the filter on its own layer, if you don’t want to obliterate the original contents of your image.
Need a quick web background image? Create a 128-x-128-pixel (or some multiple of that size) image and apply the Clouds filter. It tiles seamlessly on your web page.