What do the message “Optimize images” mean in WordPress Speed Optimization, and what can you do?
This is one of the most straightforward optimization steps to make. It means you can apply more compression to the images mentioned in the report. You can sometimes save up to 80% of the page load time by spreading reduction to photos. That’s much work!
WordPress Image Optimization
Often beginning website builders use images that are delivered in raw format. These are usually images of several MBs (Megabytes) in size. However, each byte of data must be downloaded when a user visits your website. The more data has to be sent, the longer it will take for the page to load. In short, every KB counts.
It is, therefore, wise to optimize images for the web. This means that you reduce the photos to the size at which they are shown on the website and, in any case, apply compression, as is the case with .jpg files. In any case, preferably use .png or .jpg images when you upload images to your website.
Photo editor programs such as Photoshop, Gimp, and Pixelmator often have special tools to make images optimized for the web.
Different forms of image compression in website speed
When you use compression to reduce the size of your images, you are leaving out data that often does not directly contribute to the quality of the picture. This data makes the image more significant than it needs to be, making it take longer to download.
You can use two compression methods when optimizing your images:
- Lossy compression (with loss of quality)
- Lossless compression (without loss of quality)
Images you save in a lossy format will look slightly different from the original without compression. However, this is not necessarily a problem. It is often hardly visible to the user. This method of saving is, in many cases, beneficial for web pages. It drastically reduces the size of images, while you do not want to show many images in high resolution.
However, when the images are an essential aspect of your website (for example, an artist’s portfolio), you will want to save them in a lossless format. All the original image information is then retained, but the image is still much more minor. Of course, lossless photos take up a lot more space on the server, so they also take longer to download. In some cases, however, this cannot be avoided.
Adjusting image dimensions
Another possibility to optimize images for the web is to adjust the image dimensions. Often people use images in their original dimensions (e.g. 2000 x 1600 px). This is great if you want to make a poster, but this is way too big for most websites.
If this image is shown in the size of, for example, 500 x 400 px, the user first downloads the original image. Then the user’s web browser scales the image to the correct size. This means that valuable seconds are lost downloading and scaling the image before it is displayed. To upload images in the dimensions in which they will be displayed on the website. Images can be easily resized using photo editor programs such as Photoshop, Gimp, or Pixelmator.
Do you want to speed up your site? You can start by checking your real WordPress performance score, by using these tools: