There are a huge number of filters that come preinstalled with Photoshop. If that doesn't satisfy your filter appetite, don't worry — an even larger number of filters can be downloaded from third-party developers, such as Alien Skin. Some third-party filters are free, but remember — in many cases you get what you pay for. The filters that are loaded when you fire up Photoshop come from the Plug-insFilters folder in Photoshop's application folder, so to install additional filters, drop them in that folder and restart Photoshop.
To apply a filter to an image, simply choose it from the Filters menu. If a selection is active, the filter is applied only to the selected region, without affecting the rest of your image. If you want to apply a filter to your entire image, make sure there are no active selections before choosing a filter.
When choosing an effect from the Filters menu, you'll find that some filters display a dialog box where you can specify options to control the effect; others, such as Blur and Solarize, can't be configured and are applied instantly when you choose them from the menu. An easy way to tell which ones will let you configure them is to pay attention to whether they have ellipses ("...") after their names in the menu. The ones with ellipses have options that can be configured; the ones without ellipses don't.
Be aware ...