An SAI file is a raster image created by PainTool SAI, a lightweight painting application for Windows. It contains a drawing created by the user, which includes one or more independent editing layers. SAI files can be saved, closed, and reopened for further editing.

SAI file open in SYSTEMAX PaintTool SAI 1.2 An SAI file is the native format used by PainTool SAI to store images. To create an SAI file, select File → New..., then select File → Save or Save as.... To open an SAI file, select File → Open.... PainTool SAI features various tools that can be applied to separate layers. Some of the tools are Pencil, Pen, Marker, Eraser, Brush, WaterColor, Bucket, and AirBrush. The program also comes with the lasso and magic wand selection tools. You can export an SAI file to various image formats, such as .BMP, .JPG, .PNG, .PSD and .TGA. To export the file, select File → Export as and choose the format.