The use of images, videos and other files can improve the quality of your blog posts and the appearance of your WordPress website. However, including too many “heavy” elements may slow down your site and affect its overall performance . Fortunately, lossless (lossy) compression can reduce file size without compromising file quality.
In this guide, we will look at lossless compression and when you should use it. Then we will see how to apply this compression method to your images and files.
Let’s get started!
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What is lossless compression?
Lossless compression can reduce file size by removing and isolating redundant data . This method can reduce files without affecting their overall quality. It is also completely reversible.
Lossless data compression uses an algorithm that looks for repetitions of words, patterns, and other unnecessary data. It then replaces this information with numbers and stores the original data in a separate index file.
It also removes metadata from your images. Therefore, this compression method creates leaner files without removing additional information.
Lossless compression is best suited for photos with transparent backgrounds and images with lots of text. These are the most common lossless file formats:
- Portable Network Graphics (PNG)
- Graphics Interchange Format (GIF)
- Compressed Files (ZIP)
- Unprocessed images (RAW)
- Bitmap image files (BMP)
In addition, lossless compression is increasingly being used for audio files. Streaming giants Spotify, Apple Music and TIDAL use this method to speed up the loading of content without reducing the quality of the music.
Why should you use lossless compression?
As mentioned earlier, lossless compression uses an algorithm to compress image formats and other file types. These are some of the most common algorithms used:
- Huffman encoding : this algorithm assigns different values to characters and their frequencies.
- Arithmetic encoding : encodes the entire file as a series of characters with symbols assigned to them.
- Run-length encoding : looks for repetitions of characters in the code, then encodes them into smaller bytes.
These compression methods reduce files without damaging their quality. You can also restore files to their original size because of their indexed data. Therefore, lossless contrasts with lossy compression , which causes irreversible changes to images and other media files.
Image compression is essential to improve the performance of your site. For starters, leaner images improve page load times. This is one of Google’s key ranking factors in determining where to place your content in search engine results pages (SERPs).
Google uses a set of metrics called Core web Vitals . The following two metrics are relevant to the images on your website:
- First Contentful Paint (FCP). FCP measures how long it takes to display the first element on your page. This could be a text or image element. If your site must load an image or other media file first, using lossless compression will speed up the loading time for your users.
- Largest Contentful Paint (LCP). Measure how long it takes to display the ‘largest element on your page. This will probably be one of your images. Therefore, if your picture has a smaller file size, your LCP score will be better.
Smaller images are not only important for SEO. They are also essential for user experience (UX). If your pages load slowly, readers may get frustrated and move away from your website.
Finally, lossless compression maintains image quality. Therefore, its use will not make graphics grainy or blurry on your website. As such, this compression method can help your site look professional to your readers.
2 Ways to apply lossless compression to your images
You can use a few different methods to apply lossless compression to your images. Some of these strategies occur within the WordPress dashboard, while others rely on external software. Let’s take a look at two different compression options!
- Use an image compression plugin.
Some WordPress image optimization plugins can compress your images using the lossless method. Using a plugin is a quick and easy option because the tool can apply compression to the entire website. Therefore, you will not need to manually edit each image, which can be time-consuming.
We recommend using the Imagify plugin to compress your images. It has multiple levels of compression built in and works for a wide range of image types:
After installing, activating the plugin and requesting an API key via email, go to Settings > Imagify in the WordPress dashboard. You will then see three different levels of optimization at the top of the page:
We recommend that you select NORMAL from the different options. This setting will apply lossless compression to your images. You can also perform this compression automatically by enabling the automatic image optimization configuration on upload .
- Use image editing software
Image editing applications, such as Adobe Photoshop and GIMP , often allow you to choose a compression method for your images. The exact options and process vary depending on the software you choose.
For example, if you have GIMP, you can use lossless compression relatively easily. First, open your photo with the image editing software. Then, go to File> Export As.
Then, open the drop-down menu under Select file type (by extension) and scroll down to select the ‘PNG image :
Click Export and you will see a popup window where you can choose the level of lossless compression from 0 to 9:
Finally, click Export to compress and save the image as a PNG. The file should now be smaller without compromising the quality of the photo.
Advantages of lossless compression
The main advantage of lossless compression is that it does not reduce the quality of the image. Therefore, it may be ideal for websites and tasks that rely on images.
For example, if you run a high-end e-commerce shop , you will probably want to display your products. Using the highest quality images can show minute details and inspire users to make purchases.
Similarly, a professional photography portfolio can also benefit from this method of compression. You can showcase your skills and possibly attract new clients and sales while maintaining high-quality photos.
In addition, lossless compression is reversible. All removed metadata is saved in separate files. Therefore, you can restore your images if you are not satisfied with the results of compression.
Finally, this compression method applies to multiple file types. If your Web site uses different elements such as GIFs, audio files, and PNG images, you will be able to compress them all to reduce your site’s loading time.
Disadvantages of lossless compression
Unfortunately, lossless compression does not offer as many performance advantages as lossy (lossy) compression . Since this method does not delete any data, the resulting images may still have significant file sizes. Therefore, you might consider using additional optimization techniques to speed up your website.
For example, we recommend enabling GZIP compression on your WordPress site. GZIP provides your general data files as small as possible to visitors, helping their browsers load your website faster. Fortunately, this type of compression is also easy to configure with a plugin such as WP-Optimize :
In addition, you might consider using a content delivery network (CDN) . A CDN uses a number of servers around the world to deliver content to users from the nearest locations. As such, this network can improve your web performance for visitors from around the world.
Conclusion
Image compression can reduce file sizes and improve loading times. As such, compression can improve the user experience of your site and increase search engine optimization (SEO).
As discussed in this article, lossless compression reduces image files without reducing their quality. This method removes metadata and repetitive information and saves it in a separate file. Therefore, you can speed up your website while maintaining bright and exciting graphics to attract your readers.