Image Optimization for Website – Why Should You Care (Updated)

Written by Ethan He

November 15, 2022


Websites nowadays often use visual content to give life to their web content. However, if the images aren’t optimized, it can cause the page to be sluggish. So choosing the right format and size can be the difference between an engaging website and one that doesn’t retain visitors.

Image Optimization techniques solve the dilemma of reducing image size without sacrificing quality. After finishing this article you will understand what image optimization is, and some actionable tips you can start implementing on optimating your images.

Today the competition for online consumers is fierce. You have to make sure that you employ effective strategies to provide the information to your consumer the best way possible so you can differentiate the business from the competition.


What is Image Optomization

Image optimization is the process of delivering images of the highest possible quality at the smallest possible size. Not an easy task for sure, but image optimization techniques can help you deliver images in the right size, resolution and quality. The point here is to keep the quality as high as possible, so you can use this technique to cut the size in half without noticeably degrading the image.

So why is image size so important ? One of the biggest causes of slow loading websites is large-sized images and videos. Keeping the images at a minimal size significantly reduces page load times, which in turn attracts visitors to stay on your website.

More importantly, Google now penalizes slow sites with low rankings, as it directly affects user experience. This makes image optimization critical to the success of your website.


Image Optimization Methods

There are three main methods you can use to deploy to optimize your images: resizing, caching or compression.


Involves optimizing by reducing the size of the image while maintaining the highest possible quality. You can reduce your image size simply by choosing the right format. For example, PNG produces high-quality images but has a larger file size than JPEG.


This method involves storing image files inside the user’s browser cache or on a proxy server. This makes the images easily accessible, reducing the image’s loading time.

Image Compression

Images can contain vectors or bitmaps. Bitmaps, also known as raster, contain pixels or tiny dots that contain unique information about colors and tones that are combined to create an image. For example, there is an image of a yellow sun and blue ocean. The compressor groups all blue pixels into the ocean category and all yellow pixels into the sun category.

This process removes redundancy by homogenizing small color differences. The most popular file formats for compressing images containing static pixel data are .png, .jpg, and .gif. Compression almost always degrades image quality. Compression can be classified as lossy or lossless.

Lossless compression – Reduces file size while preserving image quality.
Lossy compression – Removes unwanted data that permanently affects image quality.

Vector images, on the other hand, are made up of paths or line art that can be infinitely scalable because they work based on algorithms rather than pixels. Since the changes in the size of the images don’t affect the image quantity, they scale better compared to raster files.


1. Choose the Appropriate Size and Format

Using different formats for your site based on your needs will help keep your upload speed down by reducing the weight of your website. Vector images are great tools for logos or icons because they are small and work with simple patterns with a limited number of colors.

PNGs are for high-quality images and usually have a transparent background. However, it is the largest of the three, so use it with caution. JPG is the most popular image format because it can display detail and color while maintaining a relatively low weight.

In general, keep JPG images under 100 KB and 1920 pixels. GIF files are limited to 256 colors, so this format is best for simple animations with little detail.


2. Using a Content Delivery Network (CDN)

Utilizing CDN for your website is beneficial not only for image files but also for the overall speed of your website. CDN can significantly reduce upload times when downloading images, by loading static images onto the closest server to the user. Image optimization can be categorized by:

Cache controls – CDN offers a user-friendly interface where you can define proxy caching policies or set rules for specific groups of files or file types. This type of caching reduces the load on the original server by eliminating the need for new visitor applications that effectively reduce bandwidth usage.

Automated compression – One of the great things about CDN is that it automates image compression by following instructions. This will allow you to choose the right balance between speed and quality for your website.

Progressive loading – This method involves first creating an image from a high-pixel version. The image is then replaced with progressively higher quality versions until the desired quality is achieved.


3. Utilize a Digital Asset Management Solution

A digital asset management solution works as a central repository, helping you organize the image library. DAM software helps image optimization by automating image file tags and format conversion, making it easier to optimize the files for uploading.

DAM software can come in many shapes and sizes and can be hosted on the cloud or on premise. With some DAM solely focused on image and video management.


4. Consider Lazy Loading

Instead of loading all your images initially, only the images displayed on the user’s screen will be visible. Replace all other images with placeholder images or spaces.

As the user scrolls through the web page, lazy loading loads the images that are visible in user’s browser’s viewing area. This will reduce the initial web page loading time, allowing your users to view your website faster.


5. Optimize Your Thumbnails

Websites such as e-commerce use thumbnails for category pages. You might think that they don’t take up much space, just because they look small. However, thumbnails can subtly increase the page load time.

By reducing the thumbnail size, you can reduce the cumulative effect of thumbnails on page load time. The ideal size for thumbnails is less than 70kb, don’t forget to name to name your thumbnail images appropriately.


Wrapping Up

Image optimization helps speed up page uploads, improve the user experience, retain visitors and improve the overall performance of your website. Therefore, following the actionable tips above is a good starting point for improving the experience of your website visitors.

If you need help implementing any of the above suggestions, please contact me! You know I am always happy to help. 

Ethan He

About Ethan He

Ethan is a Full Stack Web Developer and SEO Specialist based in Pittsburgh, PA. In his free time, Ethan enjoys working on various projects involving Ruby, Vue and AWS applications.

Ethan graduated from The Firehose Project coding bootcamp in 2016 with a focus on Ruby on Rail and Computer Software engineering.