Inkscape is a vector graphics editor similar to Illustrator, Freehand or CorelDraw, but it has the advantage of being free as well as free code. Like the other programs mentioned, Inkscape supports SVG (Scalable Vector Graphics) format but can also import other formats like JPEG, PNG, and TIFF; And export to PNG (alpha transparency) and other vector-based formats.
The difference with raster graphics editors like Photoshop or Gimp is that Inkscape stores its graphics in vector format. Vector graphics describe the actual shapes and objects of an image, regardless of the resolution of the image. A rasterization engine uses this information to determine how to draw each line and curve. Inkscape uses Potrace as a vectorized bitmap engine.
Inkscape is a powerful drawing tool, capable of working with layers, gradients, transparencies, gradients, strokes, shapes, clones, markers, alpha channel mixes, patterns, groupings, freehand drawing, text, and more.
As in Photoshop or other professional design or drawing tools, the use of layers provides greater flexibility since each layer contains a part of the drawing content, allowing to work with them independently.
This graphic tool can be used for several purposes: to create banners, icons, maps for games, pets and logos for web pages, and much more. In the official wiki you can see documents, tutorials, galleries, and so on.
Inkscape 0.92 is the latest version, updated in January 2017, of this excellent multiplatform vector drawing software (Windows, Linux, Mac OS X) that can be downloaded for free.