GIF is a format for the exchange of images. It is a popular format graphics. Capable of storing compressed data without loss of quality in the format of not more than 256 colors. GIF format was developed in 1987 (GIF87a) by company CompuServe for transferring raster images over networks. In 1989, the format has been modified (GIF89a), have been added support transparency and animation.
This format is a vector images file in the Sketch Drawing program, which serves to edit and create interface designs, applications and software shells. SK-files contain objects and layers which can be edited independently of each other.