TLA for Run Length Encoding
, a type of compression that is based on the fact that long, continuous series of same byte pattern
s can be efficiently stored by saying "this
byte pattern, and this much of it" - for example, "aaaaaaaaaaa" compresses to "11 'a':s".
While this form of compression is pretty weak in general use, it is pretty efficient in specific circumstances - for example, if an image has large continuous areas of same color.
Some image file formats use RLE compression optionally; these include BMP and TGA. Windows start up splash screen images, up to the 3.x era, were typically RLE-encoded bitmaps (with .rle file extension too).
Thanks to wertperch for reminding about Windows splash screens