Abstract: Image processing is one of the widely used computation problem specifically identifying, understanding, beautification and compression. Today wide variety of image file formats is available with different clarity and size. This paper describes the basic process of compressing the bitmap image file and then comparing the compressed file with original one. The process involves lossless compression. Entire process is implemented in programming language and tries to understand various segments of bitmap file. Based on the number of unique colors in bitmap file, it compresses the file to store only single value for each different color and then comparative study of both the formats is applied using different charts to reach to a specific conclusion to achieve the desired performance criteria in form of size of the compressed file. File is compressed at some level of different colors and then after the technique applied is not suitable. To find out these criteria experiments are made on different colored image to reach to a conclusion. At last paper is concluded with future scope and enhancement.