How images affect ranking in Google

The exhaustive list of factors affecting a resource's ranking is known today only to Google's own staff. Everyone else — whatever their level of competence — can only state how a particular factor affects a site's position in the results.

And while there is a certain clarity about text content, until recently there was no unambiguous answer to the question of how graphic content affects a resource's ranking.

Google's official position

A recent statement by John Mueller, a search quality specialist working with webmasters, changed the situation. Answering users' questions on Twitter, Google's leading analyst said roughly the following.

1. On the one hand, adding graphic content has no automatic effect on a site's ranking. Whether a page has images or not will not be the factor that decides a resource's position in the search results.
2. On the other hand, the presence of images, their relevance and their high quality can affect how visitors perceive a resource. So an indirect effect on ranking, through behaviour signals, is entirely possible.

Mueller also touched on the use of stock photographs and images. According to him there is no direct connection between having stock photos on a site and the resource's position in the search results. But they can affect the results in Google image search — having identical photographs on several sites may not be the best of decisions.

How do you improve a site's positions through images?

As Mueller's statements make clear, graphic content — photos and images — can after all affect a site's ranking in Google. So their optimisation deserves attention too. Follow the recommendations in this section and changes to your graphic content will tell positively on the site's positions in the search results.

So what needs doing?

Use relevant, quality graphic content

Graphics — pictures and photos — should match the subject of the article, and it is best to place them beside text that corresponds to the image. That improves behaviour signals and tells positively on ranking.

Image quality is another important factor: blurred or badly encoded graphics spoil the impression a resource makes, both on visitors and on search engines.

Original images are a plus for ranking

Using unique graphic content that appears nowhere else on the internet has a positive effect on a resource's position in the results. Besides that:

1. Do not use content protected by copyright (even for non-commercial use, choose images with an open licence).
2. On stock sites, choose the least overused images.
3. Process stock pictures in a graphics editor — sometimes simple cropping is enough to change the impression radically.

Always fill in the title, the alt and the captions

Filling in these fields when uploading an image gives the search robot extra information. Graphics with a title and an alt written out will "beat" graphics without detailed attributes, or with a meaningless string of digits in those fields.

Images are also worth captioning on the page itself. First, that is extra information for the search robot. Second, a caption catches the eye of a visitor skimming for the information they need.

Use image names that say something

Google's search robot reads not only the title and the alt but the information in the name of the graphic file itself. If the name is relevant to the image, the search engine gets extra information for ranking your resource.

Use images in suitable formats

Everything here is fairly simple:

1. JPEG — the default format.
2. PNG — the format used when the transparency of the main layer has to be preserved.
3. WebP — an alternative to JPEG/PNG that reduces file size. The drawback is that Safari does not work with this format.
4. SVG — the format for icons and logos. It scales beautifully without losing quality.

Compress graphics without losing quality

Here it matters to keep a balance between three parameters:

1. the picture's weight in KB.
2. The picture's dimensions.
3. Visual quality.

For compression and resizing you can use either Photoshop or free online services such as TinyPNG/TinyJPG or ImageOptimizer.

Besides that, previews can be used to speed a site up, with full-size images loading when the visitor clicks.

Upload graphics at the right size

That means a picture should be uploaded at the size it is displayed at on screen:

1. If the size is smaller, the image will be stretched when displayed and the quality will suffer.
2. If the size is larger, the site will load heavy graphics for nothing and loading speed will fall. The result is a risk of losing positions in the results.

A sitemap improves indexing

Not every image can be indexed by search robots. A sitemap file solves that problem even when the graphics are loaded using JavaScript, for instance.

Use structured markup

So that graphic content on the site looks equally correct when shared and when viewed directly, use structured markup:

1. Open Graph — for the most effective presentation on Facebook.
2. Twitter Cards — for presenting a page on Twitter (Open Graph will do for that too, incidentally).
3. Schema.org — for correct snippets in the search results.

Host your graphic content on your own hosting

Using third-party hosts for graphics saves space. But on the other hand it raises the risks: the graphics may load slowly, or the host may fail, and then the pictures will not load at all.

So the optimal route is to choose quality, reliable hosting with enough disk space and upload the images there. Host4Biz will keep a site running reliably even with a large number of images.

These are of course not all the tips for optimising graphic content. But provided you use quality and mostly original images, following these recommendations will raise your resource's position in the search results.