Can Alt Tags Be Too Long?

Writing by Nick Stamoulis Tweet

An interview with Peter Linsley, Google’s Image Search product manager, is a very good read. One of the questions Eric Enge asks is “When does it (alt tag) become too long?” Good question, Eric.

And I like Peter’s answer a lot:

Obviously there is no hard and fast rule. I would just think of how the user would feel about it. I think if it’s a very long description of all the details of the image, it’s probably something that would be more useful on the webpage itself. A good rule of thumb is just to say, here is what’s in the image, and then you can put a title, caption, and description elsewhere on the page. I would treat it like an image title, and if you think about the title of an HTML page, I would give the same sort of treatment.

In other words, you don’t want to write a book, or a paragraph. Probably, just one line or sentence is enough to describe most photos. The main idea behind the alt tag is to describe the photo so that someone who can’t see the photo can know what’s in it. Sometimes, all that takes is three or four words. Sometimes, it might require more.

But one thing that I don’t think was stressed enough is that the alt tag should make the photo relevant to the text on the rest of the page. This is the great imperative. Yes, describe the photo as simply and accurately as you can, but do so in such a way that you get your primary keyword, or a related word, in that description.

Let’s say you have a photo of someone dancing with a monkey at the Fort Worth Zoo (that’s Fort Worth, Texas). You could write “dancing with a monkey at Fort Worth Zoo”. But is the fact that you are at the Fort Worth Zoo relevant to your surrounding text? If not, leave it out. If you are writing a page about mailing letters through the U.S. Postal Service and you are comparing the mail service to dancing with monkeys – suppose your opening sentence is “I went to the post office today and I swear it felt like I was dancing with a monkey.” Now, your photo is a photo of someone dancing with a monkey. You could use the following sentence as your alt tag: “U.S. Postal Service employee dancing with a monkey.” Or, you could use a sentence like “Mailing a letter is like dancing with a monkey.”

I think you get the point.

The idea is to describe that photo so that someone who can’t see the photo knows what’s in it. But you also want the search engine to know that it is relevant to your page in some way. If you just use “dancing with a monkey” as your alt tag then you miss the opportunity to mention that it’s really about mailing a letter through the U.S. Postal Service. Note, however, that you do not have to use your primary keyword exactly. The search engines will also use surrounding text on the page to associate the photo with the content so if you just include some contextual description that ties the post together with your content’s main theme then that should be enough.

Disclaimer: I am not saying that using the U.S. Postal Service is like dancing with monkeys. For illustration purposes only. And no monkeys were injured in the writing of this blog post, though I might have butchered somebody’s alt tag, or wrote the correct one for the photo above!