In today's ever-evolving digital landscape with Generative AI products like those of Dall-E, Modjourney, Canva, etc. images have taken over the internet. Images and Videos have now become an integral part of storytelling for various developers, designers, and product builders.

Having fantastic and high-quality images, however, can take a toll on your website or app. With higher-resolution of images, the file sizes increase, which also means slower loading times for the users.

Today, users are having increasingly shorter attention spans, Thanks to Tiktok and other short video formats, sluggish image loading or slow video buffering can lead to a significant drop in engagement.

Why Optimizing Images is Important for Your Business?

According to Google, 53% of the users abandon a webpage if it takes more than 3 seconds to load. In 2023, Images contribute to 61.3% of the download size of a Web page on average.

Illustration on how Slow Page load times impact your users
Illustration on how Slow Page load times impact your users

Major search engines like Google factor in Site Speed and image optimization when determining website rankings as per their Web Core Vitals and Lighthouse Score. Hence Optimising images and videos has become a fundamental necessity to build a fantastic digital product in the modern era. Marissa Mayer (ex-CEO Yahoo, ex-VP, Google) even went on to comment publicly that users mostly respond to the Website Speed!  

Hence, it is of paramount importance that we take advantage of image optimization best practices by keeping the file sizes smaller using compression algorithms and making load times faster. This directly impacts your bandwidth and storage costs as well.

As per the Amazon's Report in 2007: "It was proven that for every 100ms extra loading time, Amazon loses a turnover of 1%"

The Power of Visual Content

Visual content holds an extraordinary capacity to captivate and retain audiences in ways that plain text alone cannot.

All the upcoming startups, D2C Brands, and high-growth organizations are now adopting high-quality images, infographics, videos, and other visual elements into their content marketing strategy, to create a more immersive and engaging experience for their audience. This approach has facilitated the effective communication of complex ideas and concepts around modern-day products and services. As it is said: "A picture is worth a thousand words.”

A Study by Forbes commenting that Images and Visuals grab most of the attention
A Study by Forbes commenting that Images and Visuals grab most of the attention

In fact, Forbes studies have shown that articles featuring images receive 94% more views than those without.

Understanding Image File Types and their Usage

One of the primary challenges developers face today, is to select an appropriate image file type for their development.

The three most historically popular image file types that are used on the internet are JPEG, PNG, and GIF.

JPEGs excel when it comes to photographs with subtle color variations and gradients.

When using a JPEG image format, consider exporting it as “Progressive”. This allows the browser to instantly load a simple version of the image before fully loading the full resolution onto the site.

PNGs are better suited for graphics or images with transparent backgrounds. Make sure you have the appropriate image dimensions, and look for the option to save as PNG-24 (or 8, if there’s no quality loss)

GIFs are ideal for simple animations or logo designs with a limited color palette. It only support 256 colors so has to be used judiciously.

WebP by Google, AVIF, and JPEG-XL are the three latest image formats that have stormed the multimedia world. They are designed to provide much better compression in a visually lossless manner.

One of the very crucial considerations when choosing an image file type is its compression level. Compression reduces image quality but also decreases file size, potentially improving loading times on web pages. Striking a balance between image quality and size is essential when optimizing imagery for your website/app.

There are two types of compression in images: 1) Lossless compression will maintain the same level of quality before and after the compression. Some examples of common lossless picture files include PNG and RAW. 2) Lossy compression will discard some elements of the photo, but typically in a way that there is no perceptual quality loss to the human eye.

Lossy vs. Lossless Compression
Lossy vs. Lossless Compression | Source

When it comes to image compression, there's a delicate balance to strike between three key factors:

  1. Compression: How significantly can the file size be minimized?
  2. Quality: To what degree does the image's visual quality suffer?
  3. Speed: How much time is required to encode the image?

For achieving equivalent visual quality, we can assess encoder performance concerning compression and speed. In our evaluation, we employ the SSIMULACRA v2.1 metric to gauge visual quality, plotted along the horizontal axis. On the primary chart's left-hand side, we represent compression performance as a percentage saving compared to the unoptimized 4:4:4 JPEG, depicted along the vertical axis. Meanwhile, on the right-hand side chart, we present encoding speed in megapixels per second (utilizing a single CPU core). The chart features JPEG XL (in red), AVIF/libaom (in yellow), WebP (in green), and mozjpeg (in white), each configured at its default speed setting.

Dotted lines signify the utilization of 4:2:0 chroma subsampling (yuv420), whereas solid lines indicate 4:4:4 (yuv444). The range spans from lower quality (approximately equivalent to q30 in libjpeg terms) to higher quality (approximately equivalent to q95 in libjpeg terms).

Compression gains vs. encode speed for JPEG XL (in red), AVIF (in yellow), WebP (in green) and mozjpeg (in white), as compared to JPEG
Compression gains vs. encode speed for JPEG XL (in red), AVIF (in yellow), WebP (in green) and mozjpeg (in white), as compared to JPEG
Conclusion Observations
WebP vs. Unoptimized JPEG WebP offers substantial savings of 25% to 35% at lower quality levels. However, the savings diminish at higher quality levels due to forced limited-range yuv420, struggling to match JPEG's full-range yuv444 quality at q90+.
WebP vs. Optimized mozjpeg Compared to optimized mozjpeg, WebP provides a relatively smaller additional gain of around 3% to 5% in savings.
AVIF vs. WebP AVIF outperforms WebP, delivering an additional 10% to 15% in savings. AVIF maintains significant savings even at high quality levels, unlike WebP with its forced yuv420. However, AVIF encoding is notably slower than WebP or mozjpeg.
JPEG XL vs. AVIF JPEG XL surpasses AVIF with an additional 5% to 10% in savings. This additional gain is more pronounced at high quality levels. JPEG XL achieves this while maintaining a reasonable encoding speed.

Step-by-Step Guide for Optimizing Images for Web and Mobile

Large and unoptimized images on your website can slow down your page load times and hence can negatively impact user experience. This hurts your SERP ranking and conversions directly. You need a strategic approach that will set you apart from competitors who may neglect this vital aspect of content delivery.

Step 1: Compressing your Images

One effective method for optimizing images is compression, which reduces file sizes without significant quality loss. Tools like Front.Space, TinyPNG or JPEGmini can help achieve this reduction in file size while maintaining appropriate image resolution.

Step 2: Responsive Design

Secondly, employing responsive design techniques enables the serving of appropriately sized images based on the user's device, ensuring an optimal viewing experience across all platforms and faster loading times.

Step 3: Use Lazy loading to render your Images

The third factor to consider when optimizing imagery is Lazy loading your images. When a user lands on your website or app, they start at the top of the page. It’s probably going to take them a moment to scroll the entire page, especially if they’re engaged right from the landing.

Instead of trying to load all the images at once, lazy loading acts under the assumption that users care most about the content they can see. So, the images within their browser view fully load first, while the other images load a placeholder first, and loads them later until the user scrolls to that section of the page.

In essence, the process of optimizing imagery isn't merely about improving user experience; it's also a strategic move to bolster SEO efforts.

Step 4: The Role of Alt Text and Metadata for high SERP Rankings

By incorporating relevant keywords into image titles, authors' names and bios, suitable image descriptions (metadata), copyright details and Alt Tags, you can enhance their visibility in search engine results pages (SERP Rankings), driving more organic traffic to your websites.

Alt Tags are also important for enhancing accessibility for users with disabilities or those with slower internet connections. The key to this is writing alt titles and tags that correlate to what your target audience is searching for on the internet search engines. To get a handle on this, you’ll need to do some careful keyword research.

Step 5: Resizing and Scaling Your Images

Lastly, Resizing and scaling your images on the web or app. The general rule for web-optimized images is to use a resolution of 72 pixels per inch (PPI). This usually results in images that look great on various devices and ensures sharp page loading. If you're showcasing your images on a high-definition (HD) screen, you can consider using a higher resolution.

Getting the dimensions of your images right is equally important. In most cases, it's a good practice to make them relatively similar to the size at which they will appear on your website. Typically, photos and graphics that are around 1000 pixels wide should display well on different devices.

However, for logos and icons, it's recommended to keep them considerably smaller, usually between 100-600 pixels wide. This ensures that they fit neatly into their designated spaces without causing any distortion.

By implementing various optimization techniques, you'll ensure that your images are delivered in high quality while maintaining swift load times across all devices.

How to Measure the Impact of Optimisation Through Analytics?

One of the most critical aspects of optimizing your media experience is measuring its impact through various analytics tools. This is where tracking metrics like page views, bounce rates, Page load time, and Avg. time spent on a page are essential.

Similarly, it is important to gauge which images and videos are being viewed the most by the users. Utilizing analytics tools such as Google Analytics or Front.Space's Image and Video Analytics, you can determine which images and videos drive the most engagement and tailor your content or marketing strategy accordingly.

What are various Tools to perform Image Optimization?

Thankfully, there are multiple image compression tools available on the internet today to assist in reducing file sizes without compromising on quality. Some notable options include Front.Space, TinyPNG,, and

Correctly naming and tagging your images with relevant keywords is equally important. This practice helps search engines understand image context and can boost your SEO rankings. You may simplify this process by using tools like Adobe Bridge or XnView MP, which enable batch renaming and tagging for multiple images simultaneously.

Lastly, select the file format properly weighing the pros and cons of each. AVIF is typically suitable for photographs, while WebP works well for graphics featuring transparent backgrounds, such as logos or icons.

If you are uncertain about which format to employ, experiment with both and determine which one best complements your website. Tools like Front.Space offers automated optimisation on-the-fly for all your images and videos. You may also refer to Canva which preset templates that optimize imagery based on its intended use (e.g., social media).

Optimising Images on Web or App: Frequently Asked Questions (FAQs):

What is image optimization, and why is it important for my website?

Image optimization involves reducing the file size of images while maintaining quality. It's crucial for websites because optimized images load faster, improving user experience and SEO ranking. Front.Space is an ideal FREE tool to facilitate the image optimisation on the internet.

Which image file format should I use for web optimization?

For photographs, JPEG-XL is a popular choice. For images with transparency, use WebP. For the best compression and quality, consider AVIF. Choose the format that suits your specific needs.

What is the significance of image alt text for SEO?

Image alt text provides a textual description of the image, making it accessible to visually impaired users and improving SEO. Use descriptive, keyword-rich alt text for better SEO rankings.

Can I use free image optimization tools, or should I invest in premium software?

Free image optimization tools & APIs like Front.Space work well for most needs. Premium software like Adobe Photoshop offers more advanced and complex features but may not be necessary for everyone.

Can I optimize images retroactively on an existing website?

Yes, you can by using image optimization tools or plugins like Front.Space to compress and replace existing images with optimized versions without changing the content.

How do I optimise a JPEG for the web?

You can optimise a JPEG with Front.Space using a single-line of code in URLs. However, Front.Space also offer a wealth of more detailed transformation options — where you can toggle image size, resolution, and quality too.

Does image optimization affect mobile responsiveness?

Yes, image optimization is crucial for mobile responsiveness. Smaller image sizes lead to faster loading times, improving the mobile user experience.

What is the most optimised image size for websites?

When it comes to image file sizes, 100KB to 250KB is generally held to be the largest range you should use for websites.

What are some best practices for image optimization for e-commerce websites?

For e-commerce sites, focus on high-quality product images, use the correct dimensions, and enable lazy loading. Ensure that alt text is descriptive and that images are well-optimized for a seamless shopping experience. You can use Front.Space for plugins on e-commerce portals like Shopify and Magento Commerce Cloud.

Are there any SEO benefits to using WebP images?

Yes, WebP images often result in smaller file sizes, which can improve page load times. Google also prefers WebP images, potentially boosting your SEO ranking.

How can I measure the performance of my image optimization efforts?

You can use tools like Front.Space's Website Analyser, Google PageSpeed Insights, GTmetrix, or Pingdom to analyze your website's performance and identify areas for improvement, including image optimization.

Which is the best image optimiser?

Front.Space has the ease and precision you need to get your images to exactly the right level of optimisation for FREE. Front.Space's API offers an extensive range of image optimization capabilities, like automation of compression accompanied by a high level of quality.