When compressing images using wcompress of MATLAB, the function returns both CR and BPP. In one instance I got CR = 4.4380 and BPP = 0.3550.

Now if we think of CR, which gives us the number of bits (of uncompressed image) represented using single bit (of compressed data). i.e., to store the data of 4.4380 bits we are now using a single bit. In that sense, the number of bits used to represent a pixel in uncompressed image is 8 bits, but now becomes (8/4.438) = 1.8 bits per pixel, but BPP is given as 0.3550. How?

Also make it clear how BPP = 0.3550 given CR = 4.4380.