What is a SAI File Type?
A SAI file is the native format used by SAI PainTool 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....
SAI PainTool has different tools that can be applied to separate layers. Some of the tools are pencil, pen, marker, eraser, brush, l' watercolour, bucket and l' AirBrush. It also comes with lasso and magic wand selection tools.
You can export an SAI file to different formats such as .BMP, .JPG, .PNG, .PSD and .TGA. To export the file select File → Export as and choose the format.