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How To Optimise Your Images For An SEO Boost


As a digital marketer, I'm sure you've got a good idea of the most important SEO techniques. It goes without saying that you keep on top of the latest Google updates, your site is mobile friendly and you've developed your social media presence and blogging.

Do you make sure you're optimising your site's images?If you don't, here's why you should and how you can easily optimise your website's images.

Why Image Optimisation Is A Great SEO Strategy

Despite being a massively under used SEO technique, optimising the images on your site can bring in a large amount of traffic from image searches on Google image search and other search engines - making it a great way to get ahead of your competitor on search.

Admittedly image search probably only accounts for about 10% of searches on Google, however if you're competing on competitive terms, 10% can be a significant number of searches and may present the only realistic opportunity to rank in SEO.

Also, following the image optimisation techniques listed below will meet a number of positive SEO criteria, which will help improve the ranking of the page on which the images are used.

Optimising Your Images

Let's get on and look at the various steps that you can follow to make sure that your website images are well optimised.

Image Alt Text

This is text that describes your image. If the image is not displayed for some reason, or it is taking time to load, it is this alt text that will be displayed in its place. It is also the text that the search engine spiders will use to understand the subject and context of the image. Alt text is also displayed when the website visitor hovers their cursor over the image. So you want to make sure that you are using them well.

If you are using a content management system like Wordpress, then you can usually specify the alt text for the images you are selecting on a page. If you are coding the website directly, or you just want to check if you images have correct alt tag, you are looking for code alt="image description" within the image tag of the image.

  1. Go into the coding of you website and search for an image by searching on ing. You should see a line of code similar to: <img src= “image-file.jpg” />
  1. If the image tag already contains alt="image description", you just need to check that the description text contains your target key phrase, if it is missing or doesn't then you'll need to add it.
  1. Make sure that your image tag is correctly closed /> after making any changes.

Tips to remember:

  • Be specific - include brand names, serial or model numbers and colour in alt tags as people often search on these
  • Do not keyword stuff alt tags - as this is more likely to hurt your rankings rather than help them
  • Only optimise relevant images, these will typically be specific product or service related images on the page that you are optimising

File Size

The file size of images can be a major factor in determining the load speed of your website pages. The faster or slower that your site loads can have a massive effect on customer engagement, so it needs to be something that you spend time on. Reports from Akamai and Gomez have show the following results:

  • Page abandonment goes up as page load times increase. After 10 seconds of loading nearly 37 percent of users have already clicked away
  • 40% of shoppers abandon websites that take more than 3 seconds to load, B2B website visitors get equally frustrated
  • 79% of shoppers won't buy from a site with poor performance
  • It only take one addition second of page loading delay to lower conversion by 7 percent

From this it is clear that website performance is critical to its success. Images are generally one of the largest resource on every webpage and nowadays most web pages have more than one image. Add these up and it soon becomes obvious how images play a part in load times.

This is why we want to shrink the file size of our images as much as possible without visually compromising them.

Well optimised images are more likely to be picked up in Google image search and faster loading pages are more likely to get well ranked in the Google search results, so you get a double benefit by spending time optimising your images.

Remember this isn't so much about the display size of the image but the actual file size of it.

Personally I use the Save For Web functionality in Photoshop when saving images. This show up to 4 versions of the image being saved, so that you can test various optimisation settings to visually see where you get the best balance of file size vs visibility of the compression. If you don't use Photoshop, have a read of this article from Mashable with a list 18 tools for image optimisation.

Filename Optimisation

The filename that you choose for your image can affect whether it is displayed in Google image search results. So you need to remember to name your images to ideally include target key phrases.

The best thing is to name your images as if you were search fort on Google. Remember to use hyphens in place of spaces for example if I was naming the file for a pair of jeans I might name the file as "dark-blue-levis-501.jpg". In this I have included the colour, brand and product identified, the file name isn't too long.

Image Captions

We don't recommend using image captions for all images, however there are some benefit to using them in the right circumstances.

Using captions on your images gives them context and makes it easy for readers of the page to read exactly what the image is of. As web page readers have a tendency to scan, using captions will help them engage.

Correctly used captions will lend context to the image that Google can use when indexing, it is also an opportunity for including a key phrase being targeted by the page. As always remember not to over-optimise your pages.

Get Started Today - Review Your Image Optimisation

Review the image optimisation on your site and check these questions:

  • Are you using alt text optimisation on all of the main images on your web pages?
  • Have you optimised the file size of all of your images?
  • Have you named all of your image files using the key phrase that is relevant to the image?
  • If image captions are appropriate on your site, have you used them and do they contain the search phrases relevant to the image?

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