The G3 format is used to compress image files in TIFF format when sending faxes. The compression algorithm allows for the use of a standard 10-times compression, which can be increased. It is used to remove excess image data, which makes it possible to reduce the size of the image and speed up delivery.
This format is used for storing bitmap images in an Adobe Photoshop project file. It is stored in uncompressed form, and it includes color spaces, layers with masks, two-color settings, layer structures and other data that allow bitmap photos to be finely edited.