This tried-and-true program is easier to use—and fun, too. The realistic digital "brushes" will bring your pictures to life in shades of watercolor, crayon, and calligraphy. 

Efficient tools:

• Pencil: draw thin, free-form lines or straight lines;

• Brush: over 150 built-in paintbrushes, such as DNA brush, Calligraphy brush, Blur brush, Ink brush and so on;

• Eraser: erase areas from image;

• Color bucket: fill the entire picture or an enclosed shape with color;

• Airbrush: sprays paint onto image;

• Shape and text: many ready-made shapes, such as Line, Curve, Oval, Star, Polygon, Cloud, Smile and so on;

• Color picker: pick a color for drawing tools from canvas;

• Crop tool: crop specific area from image;

• Selection tools: rectangle selection, ellipse selection, free-form selection and polygon selection;

• Zoom tool: zoom in/out the canvas;

• Hand tool: translate the canvas.

Drawing functionality: 

• Supported selection modes: normal, union, intersect, subtract;

• Resize/translate selection; 

• Stroke/fill selection;

• Supported blend modes: normal, darken, lighten, soft light, hard light, and so on;

• Complete keyboard shortcuts support;

• Basic image functions: rotate, flip, resize, crop;

• Support transparency color.

Other features:

• Create new image from system clipboard.

• Drag images from web browser or Finder onto canvas;

• Zoom by gesture;

• Paste from an image file;

• Supported file formats: png, tiff, bmp, jpeg, gif.

and much more ... 

Compatibility: OS X 10.10 or later 64 bit