PNG
From GDWiki
PNG, or portable network graphics, is an image file format aimed at portability and openness (no patents). It uses lossless compression (using the zlib library) and supports a wide range of image formats. It is comparable to the GIF format. Two advantages to using PNG graphics are its support for alpha transparency and 16.7 million colors. Unlike the GIF format, PNG does not support animated images unless using APNG, an extended version of PNG.
[edit] Compression
It is quite common for many graphic editing programs (ie Microsoft Paint or Adobe Photoshop) to implement less-than-optimal compression to reduce the time it takes to save to file. Many tools are available to help reduce the file size of PNGs without any visual changes. Note that this does not mean they are lossless - some algorithms will remove information that is not needed to retain the original image.
- PNGOUT
- PNGCRUSH
- OptiPNG
- PNG Monster - Implements a variety of PNG compression utilities into a GUI, supports batching (Open source, VB6)
