What is PNG?
PNG stands for 'Portable Network Graphics' and next to the GIF and JPEG is one of the most popular graphic file formats used today.
PNG offers lossless data compression - graphics saved in PNG format don't lose their quality. This fact is extremely important for all web-designers, because no one wants their graphics look fuzzy when extracted from Photoshop. However, the best thing about PNG files is their support for transparency including alpha channel (the percentage value of transparency).