October 3, 2024

How To Optimise Images To Improve Web Performance

Research conducted by Google indicates that a mere 10 seconds of loading time can lead to a 123% increase in a website’s bounce rate. Slow-loading images can significantly impact the overall performance of a site, potentially driving visitors to seek alternatives. A prevalent challenge in image optimization is that decreasing the file size often results in a corresponding decline in image quality.

In this article, we will provide several strategies to optimize images for the web while preserving their quality. Ultimately, optimized images enhance the SEO of your website, improve loading times for your pages, and encourage visitors to continue exploring your site rather than navigating to a competitor’s.

What Is Image Optimisation?

The process of image optimization entails decreasing the file size through methods such as compression using specialized software or altering its dimensions. Additionally, it may require providing images in specific formats, sizes, resolutions, and quality levels that achieve the minimal file size while remaining appropriate for the content, page layout, device compatibility, and user requirements. This process encompasses adjustments to the image format, size, and resolution to strike a balance between quality and loading speed, which is essential for enhancing web performance and user satisfaction.

How To Optimise Images For Web and Site Performance

Image optimization involves achieving a balance between the quality of an image and minimizing its file size. Prior to uploading an image to your website, you can utilize specialized tools or plugins for optimization (which will be discussed further below). Let us now explore various methods of image optimization that will help maintain this quality-file size equilibrium.

Start With High Quality Images

The most effective method to enhance your website’s performance is to select images that possess impeccable quality from the outset. Stock photography platforms such as Unsplash, Pixabay, and PicJumbo can provide such images. However, a potential drawback is that these images may be quite large, necessitating further size reduction. To achieve this, you may utilize software such as Photoshop, Pixelmator Pro, or other similar tools.

Choose The Right Format

Another option is to select the file format that provides the best quality and file size balance. These are the most common types of files you can use:

JPEG

• Compression: JPEG offers high compression rates, suitable for continuous-tone images like photographs, but higher compression levels may affect image quality.
• Image type: Ideal for photographs with subtle color variations and details.
• Compatibility: Supported by almost all browsers and devices, making it versatile for web use.

PNG

• Transparency: PNG supports alpha channel transparency, making it suitable for graphics, logos, and images requiring transparency.
• Lossless Compression: Preserves image quality but results in larger file sizes compared to JPEG.

WebP

• Compression: Supports both lossy and lossless compression, transparency, and animations, providing significant file size reductions compared to formats like PNG and JPEG without compromising quality.
• Lossless compression: Lossless WebP images are 26% smaller than PNGs, while lossy WebP images are 25-34% smaller than equivalent JPEGs at similar quality levels.
• Compatibility: The format is supported by major browsers like Google Chrome, Safari, Firefox, Edge, and Opera, as well as various image editing tools, making it increasingly popular for web use.

HEIC

• Compression: The format offers superior compression capabilities compared to traditional formats like JPEG and PNG. HEIC files are encoded using HEVC (High Efficiency Video Coding), allowing for high-quality images with smaller file sizes, making them ideal for efficient storage and transmission of images on devices like iPhones and iPads.
• Conversion: HEIC files can be converted to more widely supported formats like JPEG or PNG using various online converters or software tools, enabling users to view and use these images across different platforms and applications.

Mind The Difference Between Lossy and Lossless Compression

In summary, lossy compression emphasizes the reduction of file size at the cost of quality, whereas lossless compression preserves image quality, resulting in larger file sizes. A more comprehensive explanation follows.

Lossy Compression

• Permanently removes some image data considered less important to reduce file size
• Reduces image quality, but the loss is often undetectable to the human eye
• Provides higher compression ratios and significantly smaller file sizes
• Commonly used formats: JPEG, WebP

Lossless Compression

• Compresses images without removing any data, preserving quality
• Reduces file size by stripping metadata and non-essential information
• Allows images to be compressed and decompressed multiple times without quality loss
• Provides smaller file size reductions compared to lossy compression
• Commonly used formats: PNG, GIF, TIFF

The decision to utilize either lossy or lossless compression is contingent upon the particular requirements of the image and the website. Lossy compression is well-suited for photographs and images where a degree of quality degradation is permissible in return for significantly reduced file sizes and quicker loading times. Conversely, lossless compression is preferable for images that contain text, require transparency, or demand high quality, such as product images or photography portfolios.

Use Image Optimisation Tools,Desktop and Online

There are many solutions you can choose to reduce an image size and optimize it for the web, be it a lossless or lossy compression. Here are some of them.

1.Photoshop

Compressing an image in Photoshop can be somewhat intricate; however, if you are a proficient user of Photoshop and possess a good level of technical knowledge, you may consider employing this method. To decrease the file size of a PNG in Photoshop, adhere to the following steps:

1. Open the PNG file in Adobe Photoshop by dragging and dropping the image into the application or using File -> Open.
2. Navigate to Image -> Image Size or press Ctrl+Alt+I.
3. In the Image Size Dialog box, decrease the Height/Width of the image to compress its size. Ensure that the option to constrain proportions is selected.
4. Click on the Resample button and choose Bicubic Sharper from the list to maintain image sharpness during compression.
5. Click OK to close the Image Size dialog box and save the compressed image.

If you’re looking for an analogue for Mac, you can use Pixelmator Pro. It works similarly to Photoshop but is a bit easier to use.

2.Compressor.io

There are numerous online solutions available that can be equally effective as desktop third-party software. One such option is Compressor.io, which accommodates a variety of image formats, including PNG. This platform employs various compression algorithms to minimize file sizes. Users have the ability to upload their images, compress them, and subsequently download the optimized versions.

Here are the steps for compressing a PNG image using Compressor.io:

1. Go to the Compressor.io website by typing “compressor.io” in your web browser.
2. Click on the “Select files” button or drag and drop your PNG file directly onto the webpage.

Compressor.io may offer some optional settings depending on the file type. For PNG files, it typically provides options for lossless and lossy compression. You can choose your preferred compression level based on your quality requirements.

3. After uploading the PNG file and adjusting settings (if necessary), click on the “Apply Compression” or similar button to start the compression process.

Compressor.io will process the image, and you’ll see a progress indicator. The time required for compression depends on the file size and your internet connection speed.

4. Once the compression is complete, a download link or button will appear. Click on it to download the compressed PNG file to your computer.
5. Save the compressed PNG file to your preferred location on your computer.

Compressor.io makes the optimisation process user-friendly with a simple interface. Just follow these steps, and you’ll be able to reduce the size of your PNG images while maintaining a satisfactory level of quality.

3.Wordpress Compression Plugins

When hosting your website on WordPress, you are not required to manage formatting or compression tasks manually. There are plugins available that can automatically optimize your image files during the upload process, as well as enhance images that have already been uploaded. Below are some of the top plugins designed to improve your images for enhanced performance.

• Imagify Image Optimizer
• Optimole
• Optimus Image Optimizer
• WP Smush
• TinyPNG (also compresses JPGs)
• ImageRecycle
• EWWW Image Optimizer

It is crucial to avoid depending exclusively on these plugins. For example, uploading 2 MB images to your WordPress media library is inadvisable, as this can rapidly deplete your web host’s disk space. A more effective strategy is to resize the image using a photo editing tool prior to uploading, and then utilize one of these plugins for additional compression.

It is advisable to verify whether your web hosting provider includes integrated tools for image optimization prior to selecting any of these tools or plugins. This can help you save time and guarantee optimal performance.