It uses a combination of the LZ77 algorithm and Huffman coding. It’s best suited for simple graphics files, where there are long runs of identical data elements.ĭEFLATE is another lossless data compression method used for PNG images. There’s run-length encoding (used for BMP files), which takes runs of data (consecutive data elements with identical values) and stores them in a single data value and count. There are a few different methods for lossless compression. It’s up to you, as the designer, to tell it how much data to disregard by setting the image compression rate. Lossy compression, on the other hand, removes some data from the original file and saves the image with a reduced file size. Basically, lossless image compression means all the data from the original file is preserved. While lossless compression is superior for many kinds of images, it’s not necessary for many others. Many people feel that they should only use image formats that use lossless compression. We’ve covered the differences between lossless and “lossy” compression, the different file types and the compression techniques they use, and guidelines for which file formats work best for different kinds of images. If you don’t understand which type of compression to use for different types of images, you’ll likely end up with one of two results: either images that don’t look as good as they could, or image file sizes that are way larger than they need to be.īelow is everything you need to know about image compression in relation to web design. But compression is an often-misunderstood topic, partly because there’s a real lack of understanding on what the different types of compression are good for.

Proper use of image compression can make a huge difference in the appearance and size of your website image files.

Free png image compression software