What is a PNG?
PNG stands for Portable Network Graphics and is the most used lossless image compression format on the Internet. Due to the legal restrictions surrounding GIFs, PNGs were created to allow for a patent-free image format that includes features such as:
- 10 - 30% greater compression than GIF images
- Gamma Correction
- Interlacing support (although not recommended with PNG images due to increased size)
- Image transparency / opacity
As opposed to JPEGs, PNG images do not lose quality during editing thus keeping the image from degrading in quality. PNGs however do not support animation, therefore a GIF should be used for this purpose.
Using a PNG optimizer such as Optimus is an easy way to reduce image file size which in turn helps result in a faster loading time and improves SEO. Since Optimus performs completely lossless compression, it optimizes PNG images by removing metadata information that does not visually affect the image. There is an option available within Optimus to disable the removal of EXIF and IPTC information, however the reduction in file size is quite minimal when this option is selected.
Depending on the amount of metadata information being stored within an image, reductions of up to 60% can be seen when using lossless PNG optimization.
Other PNG optimizers perform lossy compression which can lead to increased compression, however also leads to a reduction in image quality. Lossy PNG optimization works by combining an image's similar colors together. This reduces the overall amount of colors in an image allowing the PNG to be converted to 8-bits instead of 24 or 32-bit.
PNG optimization with Optimus
Optimization is quick and easy with the Optimus WordPress plugin. It can also be used to optimize images directly via curl or the Image compression API.
The following example will demonstrate how to optimize PNG images via Optimus on a WordPress installation.
- Find an image you wish to optimize via Optimus. The initial size of this PNG image was 497 KB.
- Once the Optimus plugin is installed and configured, upload the image to the WordPress Media Library.
- Once the image has been uploaded to WordPress and optimized by Optimus, the reduction in image size is now displayed next to the image in the media library. In this case, Optimus was able to optimize the PNG image by 40% resulting in a new file size of 293 KB.
PNG optimization is essential when seeking to optimize a website. With smaller images the end user does not need to wait as long for the files to download from the server, however they will still receive the same great quality. A faster loading website also helps towards better SEO as search engine algorithms take website loading times into account when ranking in the SERPs.
For a comprehensive article including everything from Optimus features to pricing, and more, read our post Smart Image Compression with Optimus WordPress Plugin