The Google image search market is growing—driven by Millennials. More than 60% say they want visual search over any other type of web search. And yet most websites are unprepared for the surge.

They’re plastered with stock photos, weighed down by large image files, and they’re choosing boring search engine listings over rich snippets on search engine results pages.

As visual search grows, these mistakes are going to become more and more costly. Today we outline the image SEO principles you need to know to capitalize on the emerging way audiences are using search engines.

Be purposeful

One of the biggest problems when it comes to images—whether it be on blog posts, in social media, or on websites (including product pages)—is that the images aren’t chosen purposefully.  They’re treated as an afterthought. Stock photos plaster the average website, and they bring little to no value to the pages they’re on.

Usually, websites are better when it comes to product images, but even then, those images may not include everything a consumer needs. You’ll often see a single image when a customer needs to see a product from multiple angles, or perhaps an expanded image or an image with callouts so they can more properly determine benefits and features.

A useful image is one that gives your customers the info they need. You have to put yourself in the mind of your consumer. Create buyer personas, administer surveys, and study user behavior to discover what your customers want to see in an image.

Great images have several attributes:

  • They’re original
  • They have descriptive file names
  • They’re in an appropriate file format
  • They have descriptive alt text (alt tags or alt attributes)
  • They’re responsive
  • They have captions

Let’s take a look at some of these attributes and how they should be handled.

Create original images whenever possible

One of the major reasons to minimize your use of stock photos is that the internet is flooded with them already, which means lots of people and organizations are using them. And stock images are less likely to be referenced in content or searched for in Google Image Search, which means they’re not going to help your SEO much.

When you make your own images, it can result in something highly valuable for SEO — backlinks. Backlinks show search engines that other websites see you as a reliable source of information.

Original, useful images include infographics of written content, image representations of statistics, or original examples.  Content creators love referencing these on their web pages because they add value, and though they’re work-intensive, they’re incredibly useful pieces of visual content because they’re packed with information. They’re also less competitive to rank with because they’re so underused.

Choose an appropriate file format

File formats are critical to SEO because they affect a ranking factor—page load speed.

To put it simply, you want your pages to load quickly. The faster they load, the better for the user. About half of your potential readers will abandon their visits if your pages take more than 3 seconds to load.

You want to have high-quality images obviously (a low-quality image is going to make your site look amateurish and hurt your brand and), but you want them to be as small as possible so that your pages load quickly.

This means you need to choose the right file type. JPEGs (.jpg) are the most common file type that you’ll find on the internet. They have small file sizes, and they’re great for photos.

On the other hand, if you have a lot of text in your images, you probably want to go with PNGs (.png). You might also choose GIFs (.gif). A GIF can be appropriate for small clips from a movie or TV show. Anything animated should use a GIF.

Here are some quick guidelines for using image file types:

Infographic of when to use different image file types for image SEO.

Resize and compress images if you can

Image optimization is critical to fast load times. This means you might need to use image compression. It’s important to find a balance between quality and the size of your images.

Large, high-resolution images might look great, but they can affect your load speed severely. On a webpage, images take longer to load because they’re larger pieces of information. When you optimize images, you reduce load times.

When deciding whether to compress an image, you have to think about what’s best for the user. For example, you do want large images on a photography website to demonstrate the quality of the work. But do you really need the same size and level of quality on a company blog? Probably not.

Good imagery draws the reader in, breaks up text, and provides extra information. But too much of it in the wrong format and you risk slowing your site speed significantly.

Once you’ve chosen your file type, you can take a few different pathways to change the size of the image.

  1. Resize the image: This just means you’re cutting pieces of the image off (cropping) or reducing the number of pixels in the image (resizing). For example, if you reduce the size of an image from 400×400 pixels to 200×200 pixels, the size of the image will be smaller.
  2. Compress the image: Compressing, on the other hand, is when you reduce the file size without changing the image quality. Compression doesn’t alter the length or width of the image, and it doesn’t reduce the number of pixels in an image.

Write descriptive image alt text

Alt text is a description you can attach to your image with HTML. It’s used by screen reading software to describe images to internet users with visual impairments.

But it’s not just useful for people. Search engines also use alt text, along with other factors like file names and image captions—to figure out what an image is.

Quality alt text is descriptive. You’re not just throwing keywords in there. You’re describing, often in a full sentence, what the reader is looking at. For example, an image of a gorilla might have this alt text: a silverback gorilla eating a carrot.

Silverback gorilla eating a carrot.

Create a relevant filename for your image

Filenames are another ranking factor because they help search engines understand what the file is about. In many cases, users upload images with filenames that are just a collection of numbers and letters.

Image file names, like alt text, should be descriptive. Unlike alt text, it should be shorter, not written in a complete sentence. For our example above, a good filename would be gorilla-eating-carrot.jpeg.

Make sure your images are responsive

Most websites today are responsive to accommodate a growing number of mobile users, which means that they alter themselves automatically to fit whatever screen a user is viewing a website on.

Images can also be responsive to a degree, but to do this, you need to use a little HTML and CSS. That said, there are also plenty of great plugins out there that can do it for you, like this one for WordPress. Yoast is another great SEO plugin to check out. Without a plugin it’s a little more complicated, and you can learn more about the process here. 

Build an image sitemap

An image sitemap is just like a regular XML sitemap—it’s a collection of metadata that helps search engines to figure out what images exist on your website and how they’re related to each other.

Not all images on a website are easily accessible by Google crawlers. For example, images that have to be accessed through JavaScript forms aren’t easy to access. Creating an image sitemap on your own is highly technical, but there are a number of plugins available that can help.

Create a thoughtful image file structure

One ranking factor that you might not have known about concerns image file structure. Essentially, it means you need to consciously create the file paths for your images.

For example, instead of putting all your images into a folder called /images/, instead you might want to create a number of folders. One might be /medications/. Another might be /doctors/. That way, the file path is helping search engines more accurately understand what category an image belongs in.

Use schema markup

Schema is a standardized method by which metadata (data about data) is given to search engines about different parts of your website

Schema makes it easier for search engines to figure out what a piece of data is. Search engines can’t always tell that an image is an image, for example, so using schema helps a search engine to see that. That makes your content more likely to show up in visual search.

Schema also improves the likelihood you show up on search engine results pages with a rich snippet. These are enhanced results on a search engine that include additional data, like images or numbers of reviews.

Mobile phone showing SERPs with and without rich snippets.

Use a content delivery network (CDN)

Speed is a major ranking factor for a reason. Internet users aren’t patient. In fact, you can lose a significant portion of potential customers faster than the time it takes to read this sentence.

One of the ways to more quickly deliver your content to users is by using a content delivery network (CDN). A CDN uses a network of servers that are physically located in different areas of the world to deliver content from your website to people faster, all based on their location.

The details get technical fast, but the outcome is that your images on your site are going to load faster for people regardless of their location. Instead of having to wait for a server on the other side of the country to load an image, the user instead gets it from a server that might only be 100 miles away.

Consider lazy loading

Another option to consider to make your images load quickly is lazy loading. Lazy loading means that a browser is only loading images that your users are actually looking at.

As soon as they scroll past, the image is replaced with a placeholder image. That means only the top of the page loads initially for a user, allowing the initial load time to be slightly faster (which you can check with PageSpeed insights).

Be careful with using lazy load—it can negatively affect search rankings because it can confuse search engines. They might only see the placeholder content.

If you decide to use lazy loading, there are some great plugins available for it.

Enable browser caching

Caching is the process by which a user’s browser holds on to certain bits of data from your website that it can use later. For example, the logo in the header of a website could be cached by a user’s browser so that, as they navigate from page to page, the browser doesn’t have to keep loading that image over and over.

Turning this on means that pages are going to load faster as your user navigates, and it also means your user is going to experience faster load times when they come back to a website for a second or third visit.

Get a complimentary SEO audit

Image SEO is one of the most powerful, yet neglected aspects of SEO. As visual search continues to surge, it’s becoming crucial to make your images available to searchers around the globe.

Though it might seem intimidating, there are plenty of ways you can start optimizing with image SEO now, like renaming your image files, adding descriptive alt text, or downloading plugins for image sitemaps and responsive imagery.

Want to see how you’re doing with image SEO? Get an instant SEO audit below. Or, schedule a free consultation to see how intent SEO can boost search traffic revenue by 700%.