How Image Format Choices Impact the UX of Your Website?

Reading Time: 5 minutes

When you visit a website and it loads quickly, looks great, and runs smoothly on your phone or computer, you’re enjoying a good user experience (often called UX).

But did you know that even a small thing, like an image file, can significantly impact how well a website functions?

That’s true, the type of image format you pick can either improve or harm how your site functions for users.

In this Design Journal article, we’re going to explain everything you need to understand about image formats, how they influence your site’s speed, appearance, and overall feel, and how to make wise choices that keep your visitors satisfied.

What is an image format?

An image format is similar to the “type” of a picture file. Just like a document can be in .docx or .pdf format, an image can come in .jpg, .png, .webp, or other types. Each image format has its advantages and disadvantages.

Some formats are more efficient for conserving storage space, while others are better suited for showcasing high-quality images.

Selecting the incorrect format can lead to slower website performance or result in low-quality photos, both of which can harm your user experience.

Why user experience (UX) matters so much?

User experience is really about how visitors feel when they come to your website. Do your pages load fast? Are your images sharp? Can they easily navigate your site on their mobile phones?

If your website takes too long to load or your images appear blurry, visitors are likely to leave.

This phenomenon is referred to as a high bounce rate, which indicates to search engines such as Google that your site may not be beneficial. This can hurt your rankings.

Therefore, the images you choose are not only about appearance, but they also affect performance, speed, and SEO.

Most common image formats (and when to use them)

Let’s check out the most common image formats and see what each one is good for.

JPEG (.jpg or .jpeg)

• Best for: Photos and realistic images
• Why use it: It has small file sizes with decent quality
• Downside: Compression can make images look blurry

PNG (.png)

• Best for: Logos, icons, and images with transparency
• Why use it: Keeps image quality high and supports transparent backgrounds
• Downside: Larger file sizes

Convert your HEIC to PNG using a free online tool without downloading any software.

WebP (.webp)

• Best for: Most web images
• Why use it: Smaller than JPEG and PNG with high quality
• Downside: Older browsers may not support it (but most do now)

AVIF (.avif)

• Best for: Super high quality and compression
• Why use it: Smaller files and great detail
• Downside: Still gaining browser support

SVG (.svg)

• Best for: Logos and icons (simple graphics)
• Why use it: Scales perfectly at any size and keeps things sharp
• Downside: Not suitable for photos.

How does image format affect user experience?

Page load speed

If your images are excessively large or not in the correct format, they will take longer to load. This results in your visitors having to wait for your website to appear.

• Bad UX: Slow-loading pages frustrate users.
• Good UX: Smaller images (like WebP or AVIF) load fast and keep users engaged.

A study by Google found that if a web page takes more than 3 seconds to load, more than half of users will leave.

Mobile-friendliness

Over half of all visits to websites are now from mobile phones. This means your images should be lightweight and load quickly on smaller screens.

• JPEG and WebP are suitable for mobile because they load quickly.
• Heavy PNGs can slow down mobile pages.

Using the correct format ensures your website looks good and functions well on all devices.

Visual quality

If your pictures are fuzzy or stretched out, visitors will see your website as unprofessional.

• WebP and AVIF maintain sharp images with small file sizes.
• JPEG may lose detail if compressed too much.
• SVG keeps icons and logos crisp and clean at any size.

Always pick the best format for the kind of image you are displaying.

Accessibility & SEO

Search engines are unable to “see” your images, so they rely on other factors, such as file size, alt text, and loading speed.

• Use alt text with every image.
• Use proper file names (like convert-jfif-to-jpg.jpg, not IMG1234.jpg)
• Choose optimized formats to help your SEO rankings.

Examples: The wrong vs. right format

Let’s look at some real examples.

Wrong image format example:

You upload a big PNG picture from your phone to your website. It’s 5MB and takes 10 seconds to load.

• Hurts UX
• Slows down the mobile
• Drops your SEO ranking

Right image format example:

You change that picture to WebP, making it 400KB, and it opens in under 1 second.

• Great UX
• Fast on all devices
• Boosts SEO

Best practices for optimizing UX with image formats

• Use Lazy Loading
  Only load images when users scroll down to see them. This makes the page load faster.
• Compress Before Uploading
  Always ensure that you compress images before uploading them from your camera or phone.
• Serve Responsive Images
  Utilize HTML <picture> tags to provide the correct image format for each browser.

<picture>
<source srcset=”image.webp” type=”image/webp”>
<source srcset=”image.jpg” type=”image/jpeg”>
<img src=”image.jpg” alt=”Optimized sample image”>
</picture>

• Use CDN (Content Delivery Network)
  A CDN enables your images to load faster from servers located closer to your visitors.
• Add Descriptive Alt Text
  Helps both SEO and users with disabilities.

What happens when you get it wrong?

Using the wrong image formats can cause:

• Long loading times
• Poor appearance on mobile
• Bad SEO rankings
• High bounce rate
• Low conversion rates

It’s a small detail with a significant impact.

Site performance after format change

One online store switched all its product pictures from PNG to WebP.

Before:

• Average page load time: 5.5 seconds
• Bounce rate: 62%

After:

• Page load time: 2.1 seconds
• Bounce rate: 38%
• Conversions went up by 20%

That’s the power of wise image choices!

Final thoughts

Picking the correct image format isn’t only for developers or designers; it’s essential for anyone creating a quick and easy-to-use website. It affects:

• Speed
• Mobile experience
• Visual appeal
• SEO

So the next time you upload a picture, pause for a moment to consider: Is this the best format for my website?

Frequently asked questions

Which image format is suitable for a website?

JPEG, PNG, WebP, and SVG are the most commonly used image formats. WebP is often the best choice as it offers excellent compression with good quality, reducing load time. SVG is great for logos and icons due to its scalability without loss of quality.

When choosing website images, it is essential to ensure that those images are?

Optimized for fast loading, responsive across screen sizes, high in quality, relevant to the content, and appropriately compressed to balance clarity with performance.

Which image format is ideal for the transparency effect on your website?

PNG is the ideal format for images requiring transparency. SVG also supports transparency and is a good option for vector-based graphics.

What role do images play in website design?

Images enhance visual appeal, communicate messages quickly, support branding, guide user attention, and improve overall user experience. Well-chosen images can make a site more engaging and trustworthy.