When discovering the right image to use, an illustration, a graphic, or a picture, the next step is to customize the image for use on your web. The ranking factors for image referencing are many but relatively basic. In terms of image search, Google is mainly concerned with the relevance rather than the popularity of the source and therefore does not take as much into consideration the risk of spam and manipulation of results as for conventional web search.
1. THE NAME OF THE IMAGE FILE
All SEO image work starts with a good filename. The biggest mistake is to keep the default file name given by the camera while creating descriptive file names rich in keywords is absolutely crucial to optimize the referencing of images.
Indeed, search engines not only crawl the text on your web page, but they also look for keywords in image file names. Without even “seeing” your visual, Google must know what it represents.
So how do you go about it? Quite simply: if your image represents a sunset over Notre Dame in Paris, the name of the file should not be DSC4536.jpg, but Notre-dame-Paris-sunset-soleil.jpg. The main keyword being Notre Dame, it appears at the beginning of the file name.
The filename should describe the product as a casual shoe or generate traffic for users seeking the 1934 Fred Perry collection.
2. THE ALT ATTRIBUTE
Alt text or alt tags is an HTML attribute applied to an image for any purpose when the image cannot be displayed. For example, when images are deactivated in a browser or when the image cannot be decoded, a screen reader can display alt text for the visually impaired.
Make sure that the alt attribute includes the Search Engine Optimization keywords of the web page and relates to / describes the image.
3. THE LEGEND OF THE IMAGE
The caption of an image corresponds to the accompanying text. This text is important for image referencing because the majority of Internet users use it when they hover over an article.
Therefore, not using captions, or not using them correctly, means missing an opportunity to engage a large number of potential readers. However, not all images require the addition of a caption. It depends mainly on the use you want to make of it, and particularly if you want this image to serve your SEO.
Overall, you should add a caption if it makes sense for the visitor and not just for SEO.
4. CONTEXTUAL INFORMATION SURROUNDING THE IMAGE
Search engines determine the relevance of images in search results in relation to the context of everything around them. In other words, Google systematically looks at the text above, below and around the images, other images, image site maps, the title, and the URL of the page to assess their relevance.
This is a reason why SEO-related picture banks tend to be underperforming, as they usually appear on a single page in the form of a gallery of hundreds of pictures. At the same time, Google is just looking for one or two hyper-relevant visuals for a specific subject.
On the other hand, Google finally seems to have reached a certain sophistication in terms of image recognition. In summary, if you optimize a photo of the koala (as adorable as it is) around keywords on Gothic architecture, the search engine will not display it in its image search results for a query associated with these keywords.
5. COMMITMENT AND POPULARITY OF THE IMAGE
As with web results, feedback from users on images is a strong signal for Google: the more clicks an image has, the higher it’s ranking.
Better images, therefore, increase the clicks that will boost the ranking of this image. In other words, if you search on Google Images and then click on the 18th image, and many people do the same, Google will move it up.
Therefore, make sure that your images are at the same time of good quality, relevant, and attractive to best meet the demand of visitors.
In addition, if your visual appears on many different sites and pages, and has been integrated several times, this also seems to have a positive impact.
6. THE DIMENSIONS OF THE IMAGE
If you perform a Google image search, you will notice that the search engine does not display, or rarely, unusual image dimensions.
Thus, images that do not correspond to standard image ratios, such as 16: 9, 4: 3, or a square format, tend to be resized by search engines to fit these dimensions.
Images such as large group photos, which lose detail when cropped for thumbnail display, may not attract attention or clicks.
7. IMAGE SIZE
In terms of UX and SEO, the loading time of your web pages is particularly important and often depends on how big your files are. The rule is simple: the larger the file size, the slower the display speed.
Image files, in particular, can have a huge impact on loading speed, especially when you load a huge image, but display it in a small size. For example, if you use an image of 2500 × 1500 pixels by displaying it at a size of 250 × 150 pixels.
So when you optimize an image:
- Make it as small as possible – in terms of download size – using the right image compression.
- Make sure that the size of the image matches the size of the image as displayed. A CMS like WordPress helps by providing the image in several sizes after downloading. However, this does not mean that the file size is optimized.
Of course, reducing the file size doesn’t mean sacrificing quality. Fortunately, there are several ways to eliminate unnecessary data and many tools to optimize the images of your website:
- The “Save for Web” command in Photoshop. When using this command, you can adjust the image to the smallest file size, while keeping an eye on its quality
- PunyPNG
- Pixlr
- FotoFlexer
- ImageOptim
- JPEGmini
- Kraken.io
It is also useful to know the different types of image files to use depending on the situation. Let’s examine the three common file types and how they affect the same image:
- JPEG: JPEG images can be greatly compressed, which results in quality images with small file sizes. In the image below, the JPEG format offers pleasant quality and small file size.
The Creative Journal 