When Windows users want to create exciting graphics using the Windows operating system, they are typically relegated to using the complementary Paint program. Paint has been around since the earliest days of Windows, right along with Minesweeper. It's a popular program, and there are even entire forums sites on the Internet dedicated to the thousands of cute drawings and digital paintings that have been made by clever, artistic people using Paint over the years. But for all its popularity, Paint's functionality is extremely limited, causing frustration for anyone who wants to do any serious image creation or editing. Most notably absent in Paint is the ability to use layers; this is where PaintTool SAI shines.

Layers allow complicated editing to be done on images. With layered editing, multiple images, like slices on a cake, can be individually, independently edited and then merged back into the same image file. For example: The select tool can be used to make a selection in an image, and then the active layer can be switched to a new blank layer, and the selection can be pasted into that new layer, leaving everything outside the selection in the previous layer. This new layer can then be edited without affecting the original layer, making entire series of edits undo-able and fully alterable.

PaintTool SAI is able to create multiple layers in images, so users can perform complicated editing and processing on images that simply wouldn't otherwise be possible. PaintTool SAI also has all of the standard features and tools one would expect from having used Paint. All in all, PaintTool SAI is a must-have utility for anyone who wants the ability to create compelling graphic content on their Windows machine.