PHP gives you a good selection of options when choosing an output format: PNG, GIF, JPEG, and WBMP to name a few. Normally, though, one is best for a certain type of image.
Generally speaking, for high-quality images with many colours or a lot of detail, the JPEG format should be preferred. JPEG saves in true colour and allows you to set the compression ratio in order to get the best trade-off between size and quality. PNGs, on the other hand, work best as a replacement for GIFs, and as such work well using limited colours. They also offer alpha transparency, and really teensy file sizes.
So, put as simply as possible: for photographs, prefer JPEGs, and for everything else, prefer PNGs. Just as an aside, and at the risk of starting a flame war, the correct pronunciations are: "ping", "jay-peg", and "jif". Note that WBMP is not Windows Bitmap as you might have first thought - it stands for Wireless Bitmap and is designed for use in limited bandwidth situations.
Want to learn PHP 7?
Hacking with PHP has been fully updated for PHP 7, and is now available as a downloadable PDF. Get over 1200 pages of hands-on PHP learning today!
If this was helpful, please take a moment to tell others about Hacking with PHP by tweeting about it!
Next chapter: Getting arty >>
Previous chapter: Creating new images
Jump to:
Home: Table of Contents
Copyright ©2015 Paul Hudson. Follow me: @twostraws.