Image optimization, tips to manage alt texts and file names

Reading time : 5 minutes

Let’s go back focusing on the importance of the visual aspect within our content, and in particular the (often overlooked) value that Google Image Search can have in terms of organic traffic: in order to be able to emerge in this parallel and vertical search engine, it is necessary to work on optimizing our visual resources, and in particular to better manage image tags. Here are some tips on alt text and file name, so to find out the difference and best practices to put into practice.

What is the alt text of images

The alternative text or alt text is a text string that serves to describe an image to “alternative” sources and to ensure maximum accessibility of resources, according to the W3C guidelines, which invites you to write texts that should not “necessarily describe the visual characteristics of the image itself, but convey the same meaning of the image”.

It must be inserted in the HTML code and, generally, it is not visible for the users of the page.

Its main goal is in fact to make the images more accessible to all users who for various reasons cannot view them, such as blind people who use screen reader: if there is no alternative text for the image, will be displayed as an empty image.

Basically, inserting an alt text allows us to set a description of the image that is read through an audio prompter and tells visually impaired people what is currently appearing on the page.

In addition, this alternative text can describe the image for people who have technical difficulties in viewing the resource, due to navigation in areas with insufficient connection to load heavy resources or from obsolete devices, or because of the choice to disable the display of images in the application of the Web browser: in these cases, on the page appears the text string set instead of an empty space.

From the technical point of view, then, satisfies user agents who are not even able to “see” images, allowing search engines to improve the understanding of the relevance of the content topic.

Then there is a linguistic clarification: even if it often occurs in the optimization language, in reality the term alt tag is improper and does not exist: the alternative text, or alt text, is precisely the alternative text attribute of the image tag.

The importance of the alt text

To summarize, therefore, alt text is important for at least 4 reasons:

  1. They improve accessibility.
  2. They can improve the relevance of the content.
  3. They are an important part of Google Image Search optimization.
  4. They can be used as anchor text for image links.

It is therefore clear why correctly inserting the alternative text is always one of the first tips to optimize images for SEO and to try to improve the ranking on Google Images; in this sense, we must avoid three mistakes that may compromise the performance of our content, namely:

  1. Not entering the alt text, that could cause problems to screen readers, who have no way to communicate the image content to the visually impaired user, reading at most the name of the image file that could be generic or inappropriate.
  2. Jam pack the alt text with useless keywords, not relevant and not descriptive of the image.
  3. Adding the alt text to all images. As said, the alternative text serves to communicate information to users: in case of purely “decorative” images, without special meanings, it is not necessary to insert the alt text, which could only be a nuisance to visitors with screen reader and still does not add any SEO value.

How to add the alt text to images

The alt text resides in the HTML code, as mentioned, and to implement it technically you simply have to insert an alt attribute to the <img> tag, such as <img src=”house.jpg” alt=”house with red bricks”>.

Much more simply put, modern CMS like WordPress offer the opportunity to change the alt text without having to work on the HTML code, going to insert the text in the appropriate field between the settings of the images added to a page or article.

On the copy front, there are some tips and best practices to write a good alt text, that is a phrase studied with the targeted optimization of keywords in a context that describes the subject of the image:

  • Brevity. A long alternative text can annoy screen reader users, so it is best to use as few words as possible to describe the image.
  • Accuracy. The text must accurately and accurately describe the image.
  • Clarity. It is not a space to make keyword stuffing, but to explain the image to those who cannot view it.
  • Avoid redundancy. Google and screen readers understand that the resource is an image: there is therefore no need to write “image of” or “photo of” in the alt text. Similarly, if the context already makes it clear that there is room for an image, alt text should not repeat the same information.

What is the title of the image

But the alt text is not the only fillable text field, in terms of SEO optimization, since there also are file names, captions and title text of images that require attention.

The caption, for instance, is the text that appears in the vicinity of the image and can be used to describe it better for readers (and is therefore different from the alt text, which as said is not visible on the front end of the site and is useful for some specific users), but it does not always serve and can be omitted (especially if the context already sufficiently clarifies the visual resource).

The title text or text title of the image, on the other hand, is an attribute used to provide additional information about the image, even if it does not serve in terms of search rankings and therefore has a minor role in the optimization work: the best practices to write an effective title suggest to choose a short sentence, direct and captivating, that perhaps integrates what we have already optimized for alternative text.

Respecting user intent and user experience in the optimization of images

Leading our work of optimizing the textual side of images – which is a relevant part as well as the technical optimization of images – should be considerations about matching the user’s intent and user experience, as suggested by Brian Harnish, and so not only the targeting of keywords.

This means first of all not doing keyword stuffing and, secondly, changing keywords when appropriate. In addition to following the best practices for images recommended by Google, according to the expert there are three precise questions that we should ask when we optimize alternative text and titles in images:

  1. Will alt text and title text help my users?
  2. Will these alternative text and text title satisfy the user’s intent?
  3. Will these texts improve the user experience?

How to optimize the file name

The last piece to consider is the name of the image file or file name, which helps Google to more precisely assess what is the subject of an image.

As Harnish says, “optimizing file names based on optimizations of alt texts and title texts can provide greater understanding, which will help images to rank in image search”.

On the practical side, in most cases it is not necessary to insert long filenames with long descriptive text: it is enough a key phrase that describes the image synthetically and precisely, making sure that the text of the file name accurately reflects the image topic.

Improving images is a part of the work on the UX

Ultimately, the work of image optimization has a relevance to the SEO and, in particular, to the ranking on Google Images, but we must not lose sight of its primary goal, which is to improve the user experience.

Therefore, it is definitely important to properly optimize images and learn the right techniques to do so, but without spending too much time on these aspects at the expense of others with a higher priority within our online marketing strategy.