The .PNG is a lossless compressed image format that has the potential to be used in web applications. It’s considered the successor to the .GIF file due to its ability to present solid chunks of color, such as in computer generated graphics and animation, in a lossless format. Unfortunately, images formatted as PNG files are capable of reaching quite large sizes, which can make them a heavy burden for websites that wish to operate efficiently. However, the file sizes can be reduced through further compression so that they are suitable for website use. There are two types of compression: in the first, the files are simply stripped of non-essential elements such as metadata to reduce the file size without a corresponding decrease in image quality. Metadata includes descriptive information, date and time, locations, digital stamps from programs used to edit it, and information about devices used in its creation. .PNG’s that have had their metadata stripped do not impact the website viewer’s experience at all.
The other way to compress a .PNG is to reduce the image quality by a small, barely perceptible amount. This works by reducing the number of colors used by the image, which can harshen details when taken to the extreme, but in normal applications does not impact the quality of the image. Users typically do not notice a difference in image quality between compressed and uncompressed .PNG files when displayed on websites.
The most obvious use of compression will be toward efforts to reduce bandwidth usage in websites. Hosting plans are much cheaper today than they were some years back, but it’s still worthwhile to minimize the amount of data-transfer on your servers in order to avoid having to buy more bandwidth than you need. However, there is also value in reducing the size of images in long-term storage on your computer or in databases. While a single image is unlikely to take up much space, a large collection of images could very well occupy a significant portion of your hard drive. By reducing the size of your .PNG files, you can save space.
You can compress PNG files in Photoshop and other photo manipulation software, but this browser-based tool will be sufficient for most applications. To use, upload your .PNG file and choose the option “compress only.” This will compress your PNG file rather than converting it into a .JPG. You will receive detailed breakdown of the compression, including the reduction in file size.