I am just trying to understand a few minor details regarding images that are compressed with lossless algorithms such as RLE. If a bmp image is compressed using RLE, when does the decompression occur when viewing the image? does the image viewer have a built-in library to decompress the image and then view it? or is it using a system library? Is the decompressed image file stored in the RAM temporarily?Do you any references for this process? 
Viewing images that compressed using lossless algorithms
image processing;data compression;encoding scheme