- Easy Paint Tool SAI includes a limited range of real media tools, including pencil, airbrush, paintbrush, watercolor, crayon and marker brushes, as well as acrylic brushes made to simulate use on paper or canvas. It also includes some standard photo-editing brushes like blur, eraser and bucket fill tools. Paint Tool SAI offers a wider range of selection tools than many other programs, including the rectangle selection, magic wand, lasso and a special selection pen that works like a brush. All drawing and editing tools work with pressure-sensitive pen tablets, changing size and opacity according to pen pressure.
- This lightweight graphics program has a relatively limited feature set outside of the basic drawing tools. Every tool can be used as a flat or variably pointed tool, to produce a range of marks. Tools can also be set to show an imitation paper or canvas texture, as well as bristle strokes. The program offers a color mixing palette and a limited range of image editing functions. These include a "Hue and Saturation" menu and a "Brightness and Contrast" menu. SAI supports transparent layers in a variety of types, including multiply, overlay and luminosity. It also supports very limited vector work on special layers. The program includes a "Transform" menu that allows users to scale, rotate or deform objects or layers and hotkeys that allow users to easily rotate the canvas and return it to its default state for easier drawing angles.
- SAI supports only a few image formats compared to higher-priced professional software. This program saves and opens files in native SAI format, Photoshop PSD, BMP, JPG, PNG and TGA formats. It can open only files saved in the RGB color space. Files in bitmap or grayscale modes will not work in SAI, and must be converted to RGB even if the final piece will not be in color.
- Paint Tool SAI works best as a companion program to a fuller-featured image editing program. Users can save files to a limited number of formats, but cannot print from SAI. SAI also offers no CMYK support, making it less useful for book and poster illustrators, who need to keep their images in a narrow gamut for printing purposes. SAI cannot create large images, restricting users to 10,000 pixels per side. Artists must work on larger images in segments, then piece them together in another program. While SAI's low resource requirements and easy drawing features make it an excellent choice for freehand drawing, it won't perform advanced functions or meet the needs of many professionals.
- Easy Paint Tool SAI is among the least expensive digital painting and drawing programs available, at only 5,250 Japanese yen, or about $66 as of time of publication. Low-end competing products cost $99 or more, while professional-grade programs can run between $430 and $999 as of the date of publication.