Image Alt Tag & File Name Best Practices For SEO & UX

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The average human brain can process an entire image in as little as 13 milliseconds.

Search engines, however, cannot. While they can try their best, search engines such as Google, Bing, Yahoo, and DuckDuckGo are still dependant on us to tell them what an image contains. This is where “alt tags” come in handy.

What Is an Alt Tag?

An “alt tag” or “alt attribute” is a line of text installed in the backend of a web page that describes an image or another attribute of the page that the code can’t fully describe. While a search engine knows the dimension, color, and text size of a website by “crawling” the code, it doesn’t automatically know that one of the images is of a tan long-haired cat wearing a red hoodie sweatshirt on a white background. Alt tags help search engines understand the image contents of your website and index them appropriately.

How Do Alt Tags Help Users/UX?

  • Alt tags help search engines to help users find what they’re looking for. In 2001, there was a sudden demand for images of Jennifer Lopez’s green Versace dress. This demand actually overwhelmed Google’s search capabilities at the time. This event has been noted as the catalyst for the building of the Google Images service. If many sites simply had the dress pictures alt-tagged as “lady in green dress”, it would have taken users significantly longer before they found the pictures they wanted. Descriptive alt tags help search engines to serve up the images that users are looking for and websites that contain those images. This ease of navigation greatly enhances user experience (UX). To put it concisely in the language of the 1982 film, Tron, alt tags fight for the users.
  • Alt tags help the visually impaired. In order to bring the content of websites to the visually impaired, there are a handful of software programs capable of describing websites in audio form. These programs use the website’s code to describe what is on the page just as a helpful friend would use their eyes and brain to process and describe what they see. One area where these programs can fail is accurately describing images. If the images on a website aren’t tagged properly, these programs are unable to tell the visually impaired visitor what images contain.

What Helps Users In Turn Helps SEO

When it comes to search engine optimization (SEO), many are hyper-focused on how to trick search engine algorithms into believing they are more relevant for a certain search query than they may actually be. This spamming is a gunshot to the foot. It’s easy to forget that search engines are in the business of serving up the most relevant results based on someone’s search. Because of this, one must display genuine relevance in order to pursue lasting results. Alt tags for images allow you to make content more easily digestible for search engines in order to make it more accessible to users. Always remember to optimize for users first and search engine optimization will naturally occur.

How To Optimize Image Alt Tags

What do you see?

It’s easy to overthink optimizing image alt tags. One of the easiest ways to keep from overthinking and wasting time is to simply describe the image as you would to a visually impaired friend. Prioritize details in order of prevalence. The following are a few examples:

Bad: cat

Good: cat in hoodie

Best: tan cat in red hoodie sweatshirt on white background

Other items to remember:

  • Keep the alt tag under its suggested length. In order to keep them succinct, image alt tags should never surpass 125 characters.
  • Don’t spam the alt tags. It can be easy to want to “over-optimize” or spam the alt tags. While “tan cat in red hoodie sweatshirt on white background” is a great alt tag, “cat hoodies red blue orange yellow for sale free shipping made in usa soft cotton many sizes” is a great way to completely disorientate search engines and the visually impaired alike. This lack of clarity can tank the image’s ranking on Google Images and may even hurt the website’s SEO.

Optimizing Image File Names

In a similar vein of image alt tags, image file names should also express the contents of the image in a natural way. They can be optimized in a way similar to image alt tags, but even more succinct with the words separated by dashes (-).

Bad: shutterstock_126236735.jpg

Good: cat-in-hoodie.jpg

Best: cat-in-red-hoodie-sweatshirt.jpg

Added bonus: This practice of file name optimization also makes managing images in a media library much easier.

To Summarize Image Alt Tags & File Names

In this piece, we learned…

  • How search engines need our help describing images
  • What an alt tag is and what it does
  • How alt tags help users
  • What helps users, in turn, helps SEO
  • How to optimize image alt tags for SEO and UX
  • How to optimize image file names for SEO and UX

Happy alt tagging!

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