STL, an abbreviation for stereolithography, is an interchangeable file format that represents 3-dimensional surface geometry. The file format finds its usage in several fields such as rapid prototyping, 3D printing, and computer-aided manufacturing. It represents a surface as a series of small triangles, known as facets, where each facet is described by a perpendicular direction and three points representing the vertices of the triangle.
A GIF or Graphical Interchange Format is a type of highly compressed image. Owned by Unisys, GIF uses the LZW compression algorithm that does not degrade the image quality. For each image GIF typically allow up to 8 bits per pixel and up to 256 colors are allowed across the image. In contrast to a JPEG image, which can display up to 16 million colors and fairly touches the limits of the human eye.
You can also convert STL into many other file formats. Please see the complete list below.