One of my friend mailed me (after reading my posts about Inkscape). He said "what's the difference between Gimp and Inkscape ? they both seem to be same..." He isn't a techi so thought of mailing him back with some basic information, here is the excerpt...
Images can be represented in computers in two ways,
1) Raster images ( bitmap ).
2) Vector images.
Raster images are represented in terms of pixels. A pixel is the smallest displayable unit. Each pixel is in turn represented by colors like red,green,blue (RGB). These pixels when arranged in rectangular fashion form an raster image. The image size is represented in terms of pixels. A 100*100 pixel image consists of an rectangular array of 100X100 pixels. Depending on the display device, you can see the appropriate image. Now if you zoom in or enlarge this image, then the quality decreases...the pixels are now displayed as square boxes. This is one of the disadvantages of raster images.
Vector images are represented in terms on points, lines, curves, polygons. Any object is represented by its attributes like position, shape, proportions, color, transparency etc., The main advantage of vector over raster is its ability to stretch or expand. As the vector image is represented by its attributes, when ever you scale the image, it expands without the loss of quality.
vector images are easily re sizable where as raster images cannot be expanded without the loss of quality.
Vector image files take same amount of memory space to store what ever the size of the image be as the number of attribute required to represent the image are same. For scalar images, as size increases, the number of pixels increases so does the memory occupied by the file.
The only disadvantage of vector images is that it is very difficult to represent real & life like images. Even if you try to represent them, they will take a lot of memory.
Coming to the actual question,
Gimp is a raster image editing software where as Inkscape is vector image editing software. If you know the difference between raster & vector image representation this single line answers your question.
The images that we capture from cameras are raster images. We use softwares like Gimp or Photoshop to edit/retouch or do some color corrections. Vector editors like Inkscape and Adobe Illustrator are widely used to create logo's, design patterns, animations and also in printing industry.
Further Inkscape uses Scalable Vector Graphics (SVG) to represent graphics. SVG is nothing but an XML file whose file format is defined by the world wide web consortium. SVG format also supports animations by allowing scripts to be included.