By Marc Woodland on November 08, 2017

Image SEO - Optimising images for search

A 2016 study by SEO training and link building experts Backlinko found that including even a single image in your content is enough to increase search engine rankings. However, when it comes to SEO, simply including an image should be considered the bare minimum.

If you want your content to stand a chance in the tooth and nail fight for top rankings then you’ll need to optimise your images, too. The good news is, the smallest changes to your process can make a big difference.

Below is a checklist of sorts on image SEO best practice with some simple tips to apply when using images for your own blog or website.

Search engine results

Use relevant images

Using images relevant to your text isn’t only good marketing practice, it’s good for SEO too. Medical students don’t expect to open a textbook on human anatomy and be confronted with a picture of a blancmange. Google (or your search engine of choice) works in the same way. But while a medical student can make a link between an image on a page and the text themselves, search engines need more context.

As Google’s Image Publish Guidelines say: “The page the image is on, and the content around the image (including any captions or image titles), provide search engines with important information about the subject matter of your image. For example, if you have a picture of a polar bear on a page about home-grown tomatoes, you'll be sending a confused message to the search engines about the subject matter of polarbear.jpg.

Wherever possible, it's a good idea to make sure that images are placed near the relevant text. In addition, we recommend providing good, descriptive titles and captions for your images.”

Remember also that while human beings may understand wit and irony, Google doesn’t. So don’t make your image choices ironic or completely out of left field.

Choose descriptive file names

A lot of people ignore image SEO best practice simply because of time. Download an image for your blog post (copyright free, of course), and it’s tempting to get it straight in Wordpress so you can get publishing. Our time is precious, and the niggly jobs are the ones that always seem to add up.

However, it’s these little things that make a big SEO difference over time. When downloading images or uploading your own, take fifteen seconds to change the image file name to help search engines to find it. The who, what, when, where and why tell a lot more than IMG0023467.JPG, as Google’s Image Publish Guidelines point out. So don’t just call your image file ‘kettle.jpg’, name it ‘whistling-kettle-boiling-on-gas-stove.jpg’ instead.

Give more information with alt text

Google’s Vision API offers powerful image analysis, helping it to decode the contents of a picture. However, Google hasn’t applied this tech to SEO so it still needs a little help to decipher exactly what’s happening. That’s where alt text comes in. This information is not only read by screen readers for the visually impaired, it is also read by Google. Good alt text helps search engines determine what’s in an image making it contextual, indexable and searchable.

For example, an article on training your dog might have an image of a dog sitting on the ground. A rich description of that image might go something like: ‘Obedient Dalmatian sits in front of owner and waits patiently for a dog treat’. The temptation to stuff your alt text full of keywords and quickly improve SEO can be almost overwhelming, but resist it at all costs. As Google points out in its Image Publish Guidelines, “keyword stuffing” results in a poor user experience and may come off as spam.

Question words

Compress image size

Super fast internet breeds demanding and impatient web users. According to Akamai and Gomez, nearly half the visitors to your site will leave if a page doesn’t load within three seconds. The biggest cause of flabby and lethargic websites? Huge image files. Trim them down using Photoshop, a web-based program such as or even Microsoft Paint! It doesn’t matter. Just make them smaller. An image 5,000 pixels wide is far too large.

The type of file you use also impacts on image size. There are three file types used for images online: JPEG, GIF and PNG. JPEG is the most commonly used, is widely supported by browsers and can be compressed to a small size - according to Medium, JPEG files can be reduced to up 90% of the original file size. GIF files are also small in size but are not a good choice for photographs as they do not support a large number of colours. PNG files are slightly larger. On the plus side PNG files can hold descriptions of the image which makes this file type a strong contender when optimising images for SEO. It’s a balance between choosing something that will enhance your image SEO, and the file type that will be most widely supported and accessible.

JPEG GIF PNG infographic

Allow others to use your images

If you’re using your own images on your website, Google recommends allowing others to use your images with attribution and a link to your site. From an image SEO perspective this is beneficial, because it increases the number of places your image will be found online and provides another path directly to your content. You can create an HTML code that allows people to embed your image in their site and includes attribution. For a guide on how to generate the HTML code and what to do with it have a look at the information provided by the Creative Commons.

Create image sitemaps

The more information you can feed search engines about your images, the greater your chance of optimising them successfully for search. Image sitemaps are another opportunity to lay on a buffet of information, such as where the image was taken or image captions, for the likes of Google to devour and subsequently index. Google recognises information in either a separate image sitemap or information added to an existing sitemap.

There is a lot of content out there and the checklist of things you can do to make yours stand out to readers and to search engines can sometimes feel never-ending. Although getting your content found and then read is a game of fine margins, don’t despair. Taking care of the details, such as optimising images for search, will give your content a better chance of being found and will provide a better overall experience for your reader.

If you’re not sure image SEO is something you can tackle with confidence and you’d rather an expert handle it, get in touch, we’d be pleased to help.

Published by Marc Woodland November 8, 2017