The XCF file format is an image file created by the GNU Image Manipulation Program (GIMP), a freely distributed image editing program. XCF files are similar in makeup to a Photoshop PSD, supporting layers, channels, transparency, paths and guides. The XCF file format is backward compatible (all versions of GIMP can open earlier versions' files) and in some cases, forward compatible. Using XCF as for data interchange is not recommended by the developers of GIMP, as there may be format changes in future versions and XCF reflects various internal data structures for GIMP.
The XCF format is designed to store the entire part of the state of the Gimp that is specific to one image, apart from undo data. An XCF file is a sequence of bytes which describes a stack of layers and channels on a canvas, which is effectively just a rectangular viewport for the layers and channels. It contains a series of data structures with the main image structure coming at the very beginning of the file. The first 9 bytes of an XCF file are the ASCII string "gimp xcf "
CorelDraw GIMP XnViewMP
eXperimental Computing Facility of the University of California at Berkeley
Development of the TGA file format began in the mid eighties. A TGA file is most commonly associated with a TARGA image file (Truevision Advanced Raster Graphics Adapter). TGA files are bitmapped images, they were originally developed for use with Truevision's (now Pinnacle Systems) high-end graphics cards which were designed for video editing. TGA files are often seen in the video and animation industry, as well as by computer game manufacturers who use the TGA format to store texture files.
TGA files can store images with a range of bits, these include 8-bit, 16-bit, 24-bit or 32-bit which is 24-bit colour with transparency. They use a palette to define all available colours in an image. TGA images have typically large file sizes as every pixel is represented by a certain number of bits (dependant on the colour depth). However, they can be compressed using simple lossless run-length encoding, which can result in greatly reduced file sizes.