PhotoSketcher is a graphics editing tool for the Mac. It applies only one effect to your pictures and that is to create a sketch out of a picture. These sketches look hand made and they are applied automatically to your pictures when you load them onto the application. To load an image, you can either drag and drop it onto the interface or use the menubar menus to open it.
When the image is loaded, you can customize the process slightly. All the changes are made from a toolbar on the right part of the screen. From there, you can increase or decrease the pen size, which makes lines thicker and blacker if you increase it. You can also choose the color of the pen. There is a feature called "Moisture", which by default is not activated. When you do activate it, the image will be darkened considerably. You can also customize the degree of moisture that you want to apply to your sketches. If you don't want to create a black-and-white sketch, you can enable the option "Colorize in original colors", which applies colors to the image where there were colors in the original one. At the bottom, you will find two sliders to add or remove contrast and saturation.
In short, this is a nice application for creating automatic sketches of your pictures. They look good and can be exported quite easily.