Portable Network Graphics (PNG), is a raster graphics file format that supports lossless data compression. PNG was created as an improved, non-patented replacement for Graphics Interchange Format (GIF), and is the most used lossless image compression format on the Internet. PNG supports palette-based images (with palettes of 24-bit RGB or 32-bitRGBA colors), grayscale images (with or without alpha channel), and full-color non-palette-based RGB[A] images (with or without alpha channel). PNG was designed for transferring images on the Internet, not for professional-quality print graphics, and therefore does not support non-RGB color spaces such as CMYK.
The ICO file format is an image file format for computer icons in Microsoft Windows. ICO files contain one or more small images at multiple sizes and color depths, such that they may be scaled appropriately. In Windows, all executables that display an icon to the user, on the desktop, in the Start Menu, or in Windows Explorer, must carry the icon in ICO format. Icons introduced in Windows 1.0 were 32×32 pixels in size and were monochrome. Support for 16 colours was introduced in Windows 3.0, while Windows 95 introduced 24-bit RGB colorspace and several larger dimensions (64x64, 128x128, etc.)