When creating visual content for your website, you’ll need to choose a compression algorithm. Compressed images consume less bandwidth than uncompressed images, allowing for faster load times. You can use either a lossy or lossless compression algorithm to make your website’s images smaller.
Lossy and lossless compression algorithms both work by removing data from images. With less data, the images will take up less storage space and require less bandwidth to download. Lossy and lossless, however, are two different types of compression.
What Is Lossy Compression?
Lossy compression involves the removal of data from an image at the cost of quality. Images compressed with a lossy compression algorithm essentially lose some of their original quality. They’ll become smaller in size, but they may look blurrier or otherwise different than their original counterparts.
Joint Photographic Experts Group (JPG) is a lossy image format. When you save an image as a JPG, you should be able to specify a quality level, or you can use your image-editing software’s default quality setting. The quality level will determine the compression ratio, which regulates how much data is removed from images.
Compression ratio represents the size of the image when uncompressed relative to the size of the same image when compressed. A compression ratio of 10:1 will make images roughly 90 percent smaller. Specifying a high quality level for an image will result in a lower compression ratio. The image may look better, but it will contain more data than it would with a low quality level. Regardless, lossy compression algorithms are those that remove data from images while affecting their original quality.
What Is Lossless Compression?
Lossless compression involves the removal of data from an image while retaining all the image’s original quality. You can use it to make your website’s images smaller. Lossless compression will remove data from the images without sacrificing visual quality.
Portable Network Graphics (PNG), as well as Graphics Interchange Format (GIF), are lossless image formats. When you save raw image files in any of these formats, you’ll compress them using a lossless compression algorithm. Alternatively, you can run previously saved images through a lossless compression tool.
Lossless compression algorithms typically work by removing nonessential data from data, such as metadata and redundant data. Nonessential data doesn’t affect the quality of images; it can be safely removed without visitors noticing. With nonessential data stripped away from them, the images will be smaller.
Differences Between Lossy and Lossless Compression
Lossy compression will affect the quality of images, whereas lossless compression preserves the original quality of images. When you apply a lossy compression algorithm to an image, you’ll create a new, smaller image of lower quality.
Images saved in a lossy format are susceptible to artifacts. Each time a JPG image is opened and saved, for example, its quality will decrease. Visitors may download JPG images from your website, followed by opening and saving them in Photoshop or similar software. Because JPG is a lossy format, JPG images will lose some of their original quality when they are opened and saved. Over time, JPG images that are opened and saved many times may develop artifacts.
For the smallest file size, there’s no substitution for lossy compression. Lossy compression will remove far more data from images than its lossless counterpart. It goes beyond lossless compression to achieve the smallest file size for images.
Another difference between lossy and lossless compression is that the former is permanent, whereas the latter is reversible. You can’t restore an image to its original quality after compressing it with a lossy compression algorithm. Compressing an image with a lossless compression algorithm, on the other hand, will allow you to restore it. You can reconstruct the removed data and, thus, restore the image to its original format.
Choosing the Right Type of Image Compression
For most images, lossy compression is the best choice. It will remove data from your website’s images. Lossless compression may result in 10 percent to 50 percent smaller images, whereas lossy compression may result in 90 percent smaller images.
Lossy compression can affect image quality, but the difference isn’t always noticeable. Most visitors won’t be able to tell the difference between an original image and a lossy-compressed image. As long as you use the right settings for it, a lossy compression algorithm won’t create blurry, low-quality images; the lossy-compressed images will look almost identical to the original images.
Because it removes more data, lossy compression has a greater impact on load times. Both lossless and lossy compression can speed up your website, but lossy compression is superior thanks to the ability to remove more data. Compressing your website’s images with a lossy compression algorithm will make your site faster.
Lossy compression is more search engine optimization (SEO) friendly. Google and Bing check load times when ranking websites. They reward websites that load quickly by ranking them above slower sites. With lossy compression, you can make your website substantially faster so that it ranks higher.
Lossy-compressed images take up less disk space. All images are stored on a server. Lossy-compressed images, though, are smaller, so they take up less disk space than lossless-compressed images. If you’re approaching your server’s disk capacity, you may want to use lossy compression.
You can easily compress JPG images with lossy compression if you use WordPress. You won’t have to take any additional steps. Uploading a JPG image to WordPress will prompt the content management system (CMS) to compress it. There are also compression plugins available, such as Smush and EWWW Image Optimizer, that you can use to apply a lossy compression algorithm to all of your site’s images.
Image compression algorithms can be classified as lossy or lossless depending on how they work. Lossy compression algorithms remove the most data, which can affect the quality of images. Lossless compression algorithms only remove nonessential data without affecting the quality of images. For an online photography website, you may want to use lossless compression. For all other types of websites, consider using lossy compression.
Of course, you can mix and match compression algorithms as well. You can use lossy compression for some images and lossless compression for other images.