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Lossy vs Lossless Image Compression

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Lossy vs Lossless Image Compression

Image compression is a method of reducing data size without sacrificing information. Image compression methods are divided into two categories:

1. Lossy compression

2. Lossless compression

The key difference between the two compression methods (lossy compression and lossless compression) is that lossy compression does not restore data in its original form after decompression, while lossless compression does.

It is a technique for reducing a large file to a smaller file that can then be decompressed back to the original size. Lossy compression returns a large file to its original state with some unnoticeable data loss, while lossless compression returns the large file to its original state with no data loss.

Reducing the size of your web images will save you precious milliseconds in load time. Both have advantages and disadvantages, which you can weigh before deciding on a website owner.

In this article, we’ll clear all your doubts related to image compression. We go over each form of image compression in greater detail below.

Before understanding the difference between the two, let us first know what exactly is Lossy and Lossless compression.

1. Lossy Compression:

A Lossy compression is a form of data compression that reduces the size of a file by removing data from it. In order to reduce file size, image quality is sacrificed. The image’s size is reduced by removing any data that the compression algorithm considers unnecessary.

The term “lossy compression” refers to the loss of any data from the original image file. This is an irreversible method. You can’t undo what you’ve done after you’ve compressed a picture this way. In most cases, you can’t go back.

When compressing data on a website, such as a source code, it’s important to make sure the code isn’t tampered with. Your code can be broken by a single piece of bad data.

JPEGS and GIFS are both lossy image formats in principle. Our eyes, on the other hand, do not distinguish between JPEGS, GIFS, PNGS, or other formats. Because of the way our eyes function, images are excellent candidates for lossy compression. Different colors cause different levels of sensitivity in our eyes. This is used for image compression since certain colors are compressed rather than others.

2. Lossless Compression:

Lossless compression reduces the size of a picture without sacrificing efficiency. This is usually accomplished by extracting redundant metadata from JPEG and PNG images.

Lossless compression reduces the size of a picture without sacrificing efficiency. This is usually accomplished by extracting redundant metadata from JPEG and PNG formats. We say typically because some other compression algorithms, such as Picsmize, take advantage of other compression options without sacrificing image quality. Some image formats, such as GIF, PNG, and BMP, are known to be “lossless” in principle. However, depending on how these formats are adapted for the internet, there could be a minor reduction of consistency (which your eyes won’t notice).

The main advantage of lossless compression is that it preserves image quality while reducing file size. The main advantage of lossless compression is that it keeps your images’ quality while reducing their file size. If you choose lossless compression for your images, you will end up with larger files as a result. As a result, you’ll have to look for other ways to improve the success of your website.

When it’s important that the original and decompressed data be similar, or when differences from the original data will be unfavorable, lossless compression is used. Executable programs, text records, and source code are common examples.

Let us now see some of the advantage and disadvantage of Lossy and Lossless images:

Lossy Compression


  • The greatest advantage of lossy compression is that it reduces the size of the image file dramatically
  • Significant file size reduction leads to faster loading times and better SEO
  • Mostly, the picture quality is preserved, ensuring that your photos look fantastic


  • The greatest disadvantage is that this is done at the expense of quality
  • The files can’t be recovered later
  • The further compact a file is, the greater the chance of perceptible variations

Lossless Compression


  • It retains maximum image quality
  • It recovers compressed data


  • The biggest disadvantage is larger files
  • Smallest file size reduction

When to use:

Many considerations go into determining the acceptable compression level. First and foremost, think about the requirements. Depending on the CMS you’re using, you’ll need to tweak those settings to keep image compression under your power. Find out when to use which image compression:

Lossy Compression: Since the loss of picture quality is so minor, it will have little impact on the user’s experience. As a result, lossy image compression can be used by almost any size or industry. Since all websites use files, smaller file sizes will help to improve the site efficiency. Photography blogs and other sites that emphasize visuals may be the only exception; these sites must balance both image quality and how file sizes impact loading times.

Lossless Compression: The benefits of image compression, such as improving site speed and SEO, are diminished because the amount of data saved is limited. As a result, lossless image compression should not be used as a first choice. This choice can only be used in exceptional circumstances where changing the image quality in some way is not an option, or if you want to restore the file in its entirety later.

Final note:

Lossy vs. lossless image optimization is a personal choice; there is no “best” image optimization. Determine what you need for your website, evaluate various options, and choose what works best for you. Only remember to keep an eye on the quality of your photos and the speed at which they load in order to avoid losing visitors or customers.