crw CRW stands for the RAW image format.This format is gaining a lot of popularity nowadays since a lot of the cameras people utilise ( the single lens reflex cameras ) are using this format. The data coming from the image sensor, in the case of the RAW format, is by far the most basic and unprocessed of all. CRW is also known as digital negatives, the RAW image files have quiet the same use as the negatives used in film photography.
sgi A .sgi extension file saves images in the original Silicon Graphics Image format. These files are originated from the library of SGI images that were there on every Silicon Graphics machine. SGI files are also referred to as RGB, IRIS or Irix RGB., .sgi image files can be saved in 8-bit color, 16-bit or 32-bit color. GIMP has the compatibility to read and write .sgi extension files and also has a dialog box that pops up to help select the compression type. The preferred compression is RLE and while it reduces the file size, it is advisable to check once it is done to ensure that the file size is indeed reduced as sometimes the size is more than the actual file size.