“…The experimental results were tested using five medical images, the attained CR between 4.3 to 7.8, with PSNR values between 50.2dB to 54.3dB. [21], proposed a hybrid lossless grayscale image compression system that combination of DPCM (third order, 2D structure, Casual model) of spatial based techniques along lifting scheme and Haar DWT of frequency-based techniques followed by entropy coding of Huffman coding. The system was tested on five standard grayscale square images of sizes 512x512 pixels, where CR was achieved between 1.025 to 2.046... [22], exploited two linear prediction models pixel-based to compress grayscale images losslessly using arithmetic coding, where the first model used two prediction forms, one of pixel intensity in Upper-Left neighbor / Upper-Right neighbor (UL/UR), the other one used Upper(U), Left(L), Right(R), Bottom(B) neighbors, while the second model used three prediction forms of one, four neighbors, where the former used the left bottom, the other used either UL, UR, Bottom Left-neighbor (BL), Bottom-Left neighbor (BR) or U,L, R,B.…”