Cloudinary Blog

Adaptive browser based image format delivery

Automatically deliver the best image format to the browser

One of the main optimization challenges for website and mobile developers is how to display sufficiently high quality images to their visitors while minimizing the image file size. A smaller image file size can lead to faster load times, reduced bandwidth costs and an improved user experience. The problem is that reducing the file size too much may lead to a lower image quality and could harm visitor satisfaction. Delivering an optimized image with just the right balance between size and quality can be quite tricky.

Selecting the optimal image format - f_auto

Some formats such as WebP and JPEG-XR are more efficient than the standard JPEG format for delivering web images, but they are not supported by all browsers: JPEG-XR is supported only in Internet Explorer/Edge browsers, while WebP is currently supported only in Chrome/Opera browsers and Android devices. The result is that the best image to deliver to your visitor depends on which browser they are using.

Cloudinary has the ability to automatically detect which browser is requesting the image and then select the most efficient image format to deliver. Just add the fetch_format parameter and set its value to auto (f_auto in URLs).

The example below displays two sample images. The image on the left uses a URL without Cloudinary's f_auto flag and is therefore delivered in JPEG format across all browsers (while being scaled on-the-fly to 300px width with its aspect ratio retained). The image on the right includes f_auto in its delivery URL and so is delivered as WebP (9.8 KB - a saving of 51%) if you are using a Chrome or Opera browser, as a JPEG-XR (12.6 KB - a saving of 37%) to Internet Explorer, Edge, and Android browsers, and as a JPEG (20 KB) in all other cases.

JPEG to all browsers

WebP to Chrome, JPEG-XR to IE and JPEG to all others

Ruby:
cl_image_tag("pond_reflect.jpg", :width=>300, :fetch_format=>:auto, :crop=>"scale")
PHP:
cl_image_tag("pond_reflect.jpg", array("width"=>300, "fetch_format"=>"auto", "crop"=>"scale"))
Python:
CloudinaryImage("pond_reflect.jpg").image(width=300, fetch_format="auto", crop="scale")
Node.js:
cloudinary.image("pond_reflect.jpg", {width: 300, fetch_format: "auto", crop: "scale"})
Java:
cloudinary.url().transformation(new Transformation().width(300).fetchFormat("auto").crop("scale")).imageTag("pond_reflect.jpg");
JS:
cloudinary.imageTag('pond_reflect.jpg', {width: 300, fetchFormat: "auto", crop: "scale"}).toHtml();
jQuery:
$.cloudinary.image("pond_reflect.jpg", {width: 300, fetch_format: "auto", crop: "scale"})
React:
<Image publicId="pond_reflect.jpg" >
  <Transformation width="300" fetchFormat="auto" crop="scale" />
</Image>
Angular:
<cl-image public-id="pond_reflect.jpg" >
  <cl-transformation width="300" fetch-format="auto" crop="scale">
  </cl-transformation>
</cl-image>
.Net:
cloudinary.Api.UrlImgUp.Transform(new Transformation().Width(300).FetchFormat("auto").Crop("scale")).BuildImageTag("pond_reflect.jpg")
Android:
MediaManager.get().url().transformation(new Transformation().width(300).fetchFormat("auto").crop("scale")).generate("pond_reflect.jpg");
iOS:
imageView.cldSetImage(cloudinary.createUrl().setTransformation(CLDTransformation().setWidth(300).setFetchFormat("auto").setCrop("scale")).generate("pond_reflect.jpg")!, cloudinary: cloudinary)

The example above demonstrates automatic format selection for images that were uploaded to Cloudinary first, either using our upload API from your server code or directly from your visitor's browsers or mobile apps.

In addition to direct uploads, Cloudinary also supports fetching images via their public URLs, manipulating these on-the-fly and delivering the resulting images optimized via a CDN. This means, for example, that you can easily integrate Cloudinary with your website without modifying your infrastructure and code. Simply prefix your image URLs with Cloudinary's fetch URL.

With Cloudinary's automatic format feature, you can also dynamically convert and deliver remote images and improve your site's performance.

For example, the following URL delivers a picture of Dwayne Johnson from a remote Wikimedia Commons HTTP URL. The remote image is fetched by Cloudinary, stored persistently in the cloud, dynamically converted to WebP or JPEG-XR as required by the user's browser and delivered optimized and cached through a high-end CDN.

Ruby:
cl_image_tag("https://upload.wikimedia.org/wikipedia/commons/6/68/Dwayne_Johnson_at_the_2009_Tribeca_Film_Festival.jpg", :width=>300, :fetch_format=>:auto, :crop=>"scale", :type=>"fetch")
PHP:
cl_image_tag("https://upload.wikimedia.org/wikipedia/commons/6/68/Dwayne_Johnson_at_the_2009_Tribeca_Film_Festival.jpg", array("width"=>300, "fetch_format"=>"auto", "crop"=>"scale", "type"=>"fetch"))
Python:
CloudinaryImage("https://upload.wikimedia.org/wikipedia/commons/6/68/Dwayne_Johnson_at_the_2009_Tribeca_Film_Festival.jpg").image(width=300, fetch_format="auto", crop="scale", type="fetch")
Node.js:
cloudinary.image("https://upload.wikimedia.org/wikipedia/commons/6/68/Dwayne_Johnson_at_the_2009_Tribeca_Film_Festival.jpg", {width: 300, fetch_format: "auto", crop: "scale", type: "fetch"})
Java:
cloudinary.url().transformation(new Transformation().width(300).fetchFormat("auto").crop("scale")).type("fetch").imageTag("https://upload.wikimedia.org/wikipedia/commons/6/68/Dwayne_Johnson_at_the_2009_Tribeca_Film_Festival.jpg");
JS:
cloudinary.imageTag('https://upload.wikimedia.org/wikipedia/commons/6/68/Dwayne_Johnson_at_the_2009_Tribeca_Film_Festival.jpg', {width: 300, fetchFormat: "auto", crop: "scale", type: "fetch"}).toHtml();
jQuery:
$.cloudinary.image("https://upload.wikimedia.org/wikipedia/commons/6/68/Dwayne_Johnson_at_the_2009_Tribeca_Film_Festival.jpg", {width: 300, fetch_format: "auto", crop: "scale", type: "fetch"})
React:
<Image publicId="https://upload.wikimedia.org/wikipedia/commons/6/68/Dwayne_Johnson_at_the_2009_Tribeca_Film_Festival.jpg" type="fetch">
  <Transformation width="300" fetchFormat="auto" crop="scale" />
</Image>
Angular:
<cl-image public-id="https://upload.wikimedia.org/wikipedia/commons/6/68/Dwayne_Johnson_at_the_2009_Tribeca_Film_Festival.jpg" type="fetch">
  <cl-transformation width="300" fetch-format="auto" crop="scale">
  </cl-transformation>
</cl-image>
.Net:
cloudinary.Api.UrlImgUp.Transform(new Transformation().Width(300).FetchFormat("auto").Crop("scale")).Type("fetch").BuildImageTag("https://upload.wikimedia.org/wikipedia/commons/6/68/Dwayne_Johnson_at_the_2009_Tribeca_Film_Festival.jpg")
Android:
MediaManager.get().url().transformation(new Transformation().width(300).fetchFormat("auto").crop("scale")).type("fetch").generate("https://upload.wikimedia.org/wikipedia/commons/6/68/Dwayne_Johnson_at_the_2009_Tribeca_Film_Festival.jpg");
iOS:
imageView.cldSetImage(cloudinary.createUrl().setType( "fetch").setTransformation(CLDTransformation().setWidth(300).setFetchFormat("auto").setCrop("scale")).generate("https://upload.wikimedia.org/wikipedia/commons/6/68/Dwayne_Johnson_at_the_2009_Tribeca_Film_Festival.jpg")!, cloudinary: cloudinary)
Remote fetched image with automatic format selection

Optimizing image quality

Cloudinary's dynamic format selection feature can be further enhanced by using it together with Cloudinary's automatic quality selection feature. Including the quality parameter and setting its value to auto (q_auto in URLs) tells Cloudinary to automatically determine the optimum quality setting for an image based on its format and contents, that results in the smallest file size while maintaining visual quality. When you add f_auto together with q_auto in the delivery URL, the Cloudinary algorithm also checks if a different image format gives a smaller file size while maintaining the visual quality.

For example, the canyons image scaled down to a width of 400 pixels and delivered with both automatic quality selection and automatic format selection (q_auto and f_auto), will be delivered as WebP (20.2KB - a saving of 45%) to Chrome browsers, JPEG-XR (24.3KB - a saving of 34%) to Internet-Explorer/Edge browsers, and JPEG (36.6KB) to all other browsers:

Ruby:
cl_image_tag("canyons.jpg", :width=>400, :quality=>"auto", :fetch_format=>:auto, :crop=>"scale")
PHP:
cl_image_tag("canyons.jpg", array("width"=>400, "quality"=>"auto", "fetch_format"=>"auto", "crop"=>"scale"))
Python:
CloudinaryImage("canyons.jpg").image(width=400, quality="auto", fetch_format="auto", crop="scale")
Node.js:
cloudinary.image("canyons.jpg", {width: 400, quality: "auto", fetch_format: "auto", crop: "scale"})
Java:
cloudinary.url().transformation(new Transformation().width(400).quality("auto").fetchFormat("auto").crop("scale")).imageTag("canyons.jpg");
JS:
cloudinary.imageTag('canyons.jpg', {width: 400, quality: "auto", fetchFormat: "auto", crop: "scale"}).toHtml();
jQuery:
$.cloudinary.image("canyons.jpg", {width: 400, quality: "auto", fetch_format: "auto", crop: "scale"})
React:
<Image publicId="canyons.jpg" >
  <Transformation width="400" quality="auto" fetchFormat="auto" crop="scale" />
</Image>
Angular:
<cl-image public-id="canyons.jpg" >
  <cl-transformation width="400" quality="auto" fetch-format="auto" crop="scale">
  </cl-transformation>
</cl-image>
.Net:
cloudinary.Api.UrlImgUp.Transform(new Transformation().Width(400).Quality("auto").FetchFormat("auto").Crop("scale")).BuildImageTag("canyons.jpg")
Android:
MediaManager.get().url().transformation(new Transformation().width(400).quality("auto").fetchFormat("auto").crop("scale")).generate("canyons.jpg");
iOS:
imageView.cldSetImage(cloudinary.createUrl().setTransformation(CLDTransformation().setWidth(400).setQuality("auto").setFetchFormat("auto").setCrop("scale")).generate("canyons.jpg")!, cloudinary: cloudinary)
Optimized image quality and format

Furthermore, when using f_auto and q_auto together, not only is the visitor's browser taken into account when deciding on the best image format, but also the image contents. For example, the Cloudinary algorithm might determine that the PNG format is a better fit for specific images that contain content such as drawings. For some images, even the PNG8 format can be automatically selected for providing great looking results with a very efficient file size.

For example, the following URL dynamically generates a 400 pixels wide version of a drawing only using automatic image quality selection (q_auto without f_auto).

Ruby:
cl_image_tag("cloud_castle.jpg", :width=>400, :quality=>"auto", :crop=>"scale")
PHP:
cl_image_tag("cloud_castle.jpg", array("width"=>400, "quality"=>"auto", "crop"=>"scale"))
Python:
CloudinaryImage("cloud_castle.jpg").image(width=400, quality="auto", crop="scale")
Node.js:
cloudinary.image("cloud_castle.jpg", {width: 400, quality: "auto", crop: "scale"})
Java:
cloudinary.url().transformation(new Transformation().width(400).quality("auto").crop("scale")).imageTag("cloud_castle.jpg");
JS:
cloudinary.imageTag('cloud_castle.jpg', {width: 400, quality: "auto", crop: "scale"}).toHtml();
jQuery:
$.cloudinary.image("cloud_castle.jpg", {width: 400, quality: "auto", crop: "scale"})
React:
<Image publicId="cloud_castle.jpg" >
  <Transformation width="400" quality="auto" crop="scale" />
</Image>
Angular:
<cl-image public-id="cloud_castle.jpg" >
  <cl-transformation width="400" quality="auto" crop="scale">
  </cl-transformation>
</cl-image>
.Net:
cloudinary.Api.UrlImgUp.Transform(new Transformation().Width(400).Quality("auto").Crop("scale")).BuildImageTag("cloud_castle.jpg")
Android:
MediaManager.get().url().transformation(new Transformation().width(400).quality("auto").crop("scale")).generate("cloud_castle.jpg");
iOS:
imageView.cldSetImage(cloudinary.createUrl().setTransformation(CLDTransformation().setWidth(400).setQuality("auto").setCrop("scale")).generate("cloud_castle.jpg")!, cloudinary: cloudinary)
Drawing with automatic quality

The result is a JPEG image (20.4KB) where, if you look carefully, you can see that the lossy nature of the JPEG format resulted in some visual artifacts. In the next example with the same drawing, we will combine both q_auto and f_auto:

Ruby:
cl_image_tag("cloud_castle.jpg", :width=>400, :quality=>"auto", :fetch_format=>:auto, :crop=>"scale")
PHP:
cl_image_tag("cloud_castle.jpg", array("width"=>400, "quality"=>"auto", "fetch_format"=>"auto", "crop"=>"scale"))
Python:
CloudinaryImage("cloud_castle.jpg").image(width=400, quality="auto", fetch_format="auto", crop="scale")
Node.js:
cloudinary.image("cloud_castle.jpg", {width: 400, quality: "auto", fetch_format: "auto", crop: "scale"})
Java:
cloudinary.url().transformation(new Transformation().width(400).quality("auto").fetchFormat("auto").crop("scale")).imageTag("cloud_castle.jpg");
JS:
cloudinary.imageTag('cloud_castle.jpg', {width: 400, quality: "auto", fetchFormat: "auto", crop: "scale"}).toHtml();
jQuery:
$.cloudinary.image("cloud_castle.jpg", {width: 400, quality: "auto", fetch_format: "auto", crop: "scale"})
React:
<Image publicId="cloud_castle.jpg" >
  <Transformation width="400" quality="auto" fetchFormat="auto" crop="scale" />
</Image>
Angular:
<cl-image public-id="cloud_castle.jpg" >
  <cl-transformation width="400" quality="auto" fetch-format="auto" crop="scale">
  </cl-transformation>
</cl-image>
.Net:
cloudinary.Api.UrlImgUp.Transform(new Transformation().Width(400).Quality("auto").FetchFormat("auto").Crop("scale")).BuildImageTag("cloud_castle.jpg")
Android:
MediaManager.get().url().transformation(new Transformation().width(400).quality("auto").fetchFormat("auto").crop("scale")).generate("cloud_castle.jpg");
iOS:
imageView.cldSetImage(cloudinary.createUrl().setTransformation(CLDTransformation().setWidth(400).setQuality("auto").setFetchFormat("auto").setCrop("scale")).generate("cloud_castle.jpg")!, cloudinary: cloudinary)
Drawing with automatic quality and format

In this case, the algorithm decided to encode the image using the PNG8 format. The image looks better, has no artifacts, and weighs even less - just 16.5KB

Summary - automatic format delivery

Delivering an image in the best format can be easily automated with Cloudinary's format selection algorithm. The feature can also be combined with automatic quality selection for a powerful and dynamic solution that delivers all your images using minimal bandwidth and maximum visual quality. For more details, see the automatic format selection documentation.

All image manipulation and delivery features discussed here are available with no extra charge for all Cloudinary's plans, including the free plan.

Recent Blog Posts

Cloudinary Product Gallery Enables Dynamic Buyer Experience

We live in a world where we spend increasingly more time online. As our routines change and adapt to new trends and technologies, we perform more and more of our daily activities in virtual environments. A key example of this is shopping. There are many reasons why online shopping has become so attractive for many buyers. A near endless variety of products is accessible from the palm of your hand. Customer reviews give buyers more confidence in their decisions. It's increasingly easy to search for attractive prices. And the list goes on. But a customer's desire to "touch" or "feel" the product is an interactive experience that can be hard to overcome when shopping online.

Read more
A Guide to Website Image Optimization and Performance

Part 1 of this series delves into the background for this guide. Here in part 2 are the ins and outs.

Wait, hear me out. I know, we just talked about this: Nobody is sheepishly pleading you, “Please, might we have just one more image on the page?” No, I’m not telling you to pick that particular fight. Instead, use a little smoke and mirrors to avoid requests for images that your audience needn’t render right away and might never need at all while loading them asynchronously—only as needed.

Read more
A Guide to Image Optimization for Website Performance

I’ve spent a lot of time thinking about the rules of putting images on the web.

For such a flexible medium as the web, software development can feel like a painstaking, rules-oriented game—an errant comma might break a build, a missing semicolon might wipe out an entire page. For a long time, the laws of image rendering seemed similarly cut-and-dry: For example, if your markups contained an img element , the singular content of its src attribute would be foisted on the audience regardless of their browsing context, period.

Read more
Digital Asset Management Platform: Meeting Customer Expectations

Consumers today expect media-rich experiences. No longer a novelty, it’s second nature to swipe through multiple photos on mobile apps, zoom in on product images for a closer look, visualize online travel reviews, socialize cool video clips while browsing, and encounter brand messages when walking into brick-and-mortar stores. These experiences weave together visual cues and clues with relevant content to create meaning and more authentic connections for customers.

Read more
How to Customize Cloudinary's eCommerce Android App

Recently we added the Cloudinary Demo - eCommerce App to the Google Play Store. This app demonstrates the best practices for optimal delivery of images on a storefront, including category pages, product pages, and a shopping cart. At the time, we published Introducing the Cloudinary Demo Android App, Part 1, which provided an under-the-hood tour of how the eCommerce Android App was designed and how Cloudinary was integrated throughout.

Read more