Image SEO: How to Optimise Your Images for SEO


When you think of optimising your website for SEO, you think of keyword rich content and top class user experience. Despite these factors being the basis of having a well optimised site, it is shocking how few webmasters optimise their images for SEO.

SEO friendly images aren’t only for the benefit of search engines, but are also used for visually impaired users who have specialist software which reads webpages aloud. If your image title tags and alt tags are misused i.e. full of spammy keywords, this delivers a poor user experience.

Why Use Images Within Your Content?

From a user perspective, content with imagery is a lot more appealing than a page full of plain text. By using images to illustrate or explain your article, you are adding more value to the page and increasing the likelihood of it being shared on social media. Images are a great way to emphasize the main point of your article or to encourage a user to click on your article from a main blog page/social media profile.

How To: SEO Friendly Images

File Types

When it comes to deciding what file type you should choose for your website images, you should take into consideration what qualities each file type has and how using each type can affect download speed.

  • JPEG (.jpg) – The most commonly used file type for compressing images as you can achieve a small file size and retain image quality however image quality deteriorates with each save
  • PNG (.png) – Becoming a more popular file size in recent years, PNG images support a large selection of colours and do not deteriorate due to resaves. However, PNG images tend to have a much larger file size than other alternatives
  • GIF (.gif) – As GIFs offer lower quality images, they are best used purely for logos and small images such as social icons which do not require intense detail. GIFs are more commonly known for creating short animations.

File Naming

An SEO friendly image begins with your chosen file name. When naming images for SEO, your file name should contain the main keyword you want that specific page to rank for. As Google cannot see the image on the page, they can read the file name which is the only means they have of knowing what the image is of. For example, if you have an image of Matt Cutts at an SEO conference you would want the file name to be matt-cuts-seo-conference-2016.jpg rather than an undescriptive file name such as file123.jpg.

Alt Tags

Alt tags offer an alternative to images. Alt tags appear when users disable images from appearing in their browser or visually impaired users are using a screen reader to read the webpage. By using alt tags you are ensuring that no information is lost and that the user does not miss out on any additional information that was included within the image. Alt tags enable you to associate relevant keywords to images; Google will see your alt tags and deem your image relevant to searches around that topic. SEO friendly images add extra value to the page it is on, if your image does not serve a purpose to the page then it should not be present as it will increase page load time.

Title Tags

Title tags can be used in the same way as alt tags but they do not necessarily have the SEO benefits of alt tags. Title text is used to provide additional information that is not essential to user experience. Webmasters tend to copy their alt tags and use that as their title tags, although this will not cause a negative impact it would be more beneficial to have your alt tags and title tags slightly different.

Image Scaling

There are multiple interpretations of the term ‘image size’, it can often be confused with file size or display size (how the image looks on the page). If you upload a large image that is 3000×2000 pixels but adjust it so it only shows at 300×200 pixels, the image will still have to be loaded. An SEO friendly image achieves a fair balance between image quality and image size.

File Size

Ideally, you want all images on your website to be the smallest possible size. By compressing your images and retaining the image quality, you will improve overall page load time which is an important ranking factor in SEO. Tools such as Photoshop have built in tools especially for this, enabling you to ‘Save for Web’ and compress your file especially for web use.

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