Images and illustrations are among the most important elements that make a website interactive. We designers often use them to give a clean and modern look to a website. Yet image optimization makes a website’s face very attractive, but it can sometimes slow down the website’s speed. And the thing is that no one is going to stay on a website whose pages load slowly. Users leave slow websites, which also has an impact on search engine rankings. The reason? Well, there are many. Read on as we address common image-optimization mistakes that directly hurt a website’s speed.
Why Image Illustrations Affect Website Speed?
Every image added to a website is uploaded to its hosting server, consuming storage space. When that image is added to a web page, it also increases the page weight and size. When a page’s size (or weight) increases, the browser will take longer to load the content unless the image is optimized according to best practices.
In addition to simple images, some developers use illustrations that may appear simple but still have large file sizes. They also slow down a website’s speed when added without proper optimization. The issue worsens on small screens, such as mobile devices, and on slow connections. Here are the most common mistakes people make when using image illustrations on websites, which can slow website performance.
1. Using a Very High Resolution
High-resolution images are not intended for websites. They are usually meant for printing on large flex or banners. Still, many use them on websites they do not need because they are very large.
So, when you upload a large image, the page size increases too much. As a result, the browser takes longer to load the image, and users opening the website will notice slow load times.
This mistake usually happens when:
- Designers export illustrations without resizing
- Site owners reuse print assets on the web
- People ignore the actual display size
This problem/mistake can be fixed by resizing illustrations to match their display size.
2. Uploading Without Compression
For websites, image compression is usually considered a good practice. Many designers compress images before uploading them to websites. But some upload images directly from design tools without compression. Know that even flat illustrations with few colors can have large file sizes.
Compression removes unnecessary data from images. Without it, browsers load extra information that users never see.
This mistake hurts speed the most on:
- Mobile devices
- Slow internet connections
- Image-heavy landing pages
As a web developer/designer, always compress all images before uploading them to your website. The smaller the image file size, the faster the web page loads.
3. Choosing the Wrong Image Format
Image format also plays a big role in website speed. Many site owners stick to one format for everything. That approach causes problems, especially for illustrations.
For example:
- PNG files work well for transparency, but often stay heavy
- JPG works better for photos, but not for flat graphics
- SVG fits icons and vector illustrations perfectly
When people choose the wrong format, the file size increases without reason.
If you don’t want to hurt your website speed, try matching the format to the illustration type. For example, you can use SVG for icons and vector designs. For the rest of the image, prefer using modern image formats like WebP. They will reduce the image file size and load quickly while maintaining image quality.
4. Ignoring Responsive Image Sizes
Many websites load the same large illustration on all devices. This means a mobile user downloads the same file as a desktop user. That practice wastes data and slows down mobile browsing.
Since most traffic now comes from mobile devices, this mistake causes serious performance issues.
Common signs of this problem include:
- Slow loading on phones
- High bounce rate on mobile
- Poor mobile speed scores
To fix this, use responsive image sizes that scale to all screen sizes. For example, by defining rules on the back end, you can serve smaller images to mobile users and larger ones to desktop users. This will help you reduce load time and ultimately improve overall user experience across all devices.
5. Loading All Illustrations at Once
Some pages load every image as soon as the page opens. This includes illustrations that appear far below the fold. As a result, the browser loads too much content at once.
Long pages with many illustrations suffer the most from this issue. Users wait longer even though they only see the top part of the page.
This can be fixed by using lazy loading. When you enable lazy loading, the image illustration section loads only when the user scrolls toward it. This means the browser will not have to wait for the full page to load on the user’s device. Ultimately, the page loads faster, and users have a smoother web experience.
How Do These Mistakes Hurt Core Web Vitals?
Google uses Core Web Vitals to measure user experience. Image mistakes directly affect these metrics.
Here’s how:
- Large images slow down Largest Contentful Paint (LCP)
- Heavy layouts increase loading time
- Poor image handling hurts overall page performance
When Core Web Vitals suffer, rankings can drop. Users also become impatient and leave sooner.
Bottom Line
Image illustrations can either help or hurt your website speed. When you make the above-discussed mistakes in using image illustrations on your website, its loading speed slows down. As a result, users leave, and rankings also drop. So, optimize images properly, focus on mobile users, and load only what matters first.
