Portable Network Graphics (PNG) format is developed as a patent-free substitute for GIF, which is used for lossless compression and image display on the network. Unlike GIF, PNG supports 24-bit images and produces background transparency without jagged edge. However, some Web browsers do not support PNG images. PNG format supports RGB, index color, grayscale and bitmap images without Alpha channel. PNG preserves the grayscale and transparency in RGB images.
BMP format
BMP is the standard Windows image format on DOS and Windows compatible computers. BMP format supports RGB, index color, grayscale and bitmap color modes. Can I specify Windows or OS/2 for the image? Format, with a bit depth of up to 32 bits per channel. RLE compression can also be specified for 4-bit and 8-bit images using Windows format.
BMP images are usually written from bottom to top; However, you can also select the Reverse Line Order option to write from top to bottom. You can also click Advanced Mode to choose a different encoding method. (Flip Line Order and Advanced Mode are most useful for game programmers and others who use DirectX. )