There is only one file type that uses the .TFW extension:
World File for TIFF
TIFF world file used by GIS applications; contains the location, scale, and rotation of a map that is stored as a TIFF image; often used for saving the world location of an aerial satellite photograph; uses the same format as JPEG World files (.JPW).
TFW files are saved in a plain text format. They store a series of lines that specify the X and Y pixel size, rotational information, and the world coordinates for the top-left corner of the image.
NOTE: TFW world files do not store actual image data, but are typically saved as a separate file alongside a .TIF file.
Updated: April 25, 2015