PNG is a raster-graphics file format that supports lossless data compression. It was developed as an improved, non-patented replacement for Graphics Interchange Format (GIF).
Technical Specifications
Lossless compression (DEFLATE). Supports 24-bit RGB or 32-bit RGBA colors. Supports alpha channel transparency.
Advantages
Lossless quality, transparency support, wide compatibility.
Disadvantages
Larger file sizes compared to JPEG for photos, not good for print (RGB only).