How To Use Alt Attributes To Increase Search Traffic

Matt Cutts recently produced a video explaining how Google looks at the alt attribute on an image tag and offers some good tips for how best to use them.

Key Points

  • Search engines have a hard time understanding the subject of an image
  • You can help search engines by adding descriptive text to the alt attribute of an image
  • Do not stuff alt attributes with keywords
  • Give your images meaningful names

Additional Thoughts

I want to add a few more thoughts on the use of an alt attribute. First alt is an attribute of the image tag and not a tag itself. I doubt the term alt tag is ever going to go away, but there is no in html. A typical image tag might look something like:


<img src="name-of-your-image.jpg" alt="description of your image" width="200px" height="100px" />

It may seem somewhat semantic to make this distinction and in reality it’s more important to use the attribute properly than worry about whether it is technically a tag or an attribute, but since writing good code is important to me I wanted to mention it.

If your image is also a link you might want to add an additional title attribute, which would describe the content you would find after clicking the link. You would add the title attribute to the link tag and not the image tag.

Again these attributes aren’t anything you should stuff full of keywords. They are part of basic on page seo, but think of them with accessibility in mind first. Imagine a person who can’t see your image and write something to describe the image for that person and not specifically for a search engine. Your alt attribute need only be a few words, but if for some reason you feel a simple sentence isn’t enough use the longdesc attribute of the image instead (longdesc=”longer description of your image”).

Further Reading

Images are an often overlooked part of search engine optimization, but image search can be a good source of traffic. If you follow the basics Matt mentions in the video and give your images descriptive names and use an alt attribute on those images you’ll probably find traffic from Google image search in your log files.

If you’d like to get a little more advanced with your image optimization here are a few additional sources to get you started.

Download a free sample from my book, Design Fundamentals.

8 comments

  1. I would think one time is enough too. To me it’s less how many times you use the keywords as it it making it read well to a real person. If you can get another keyword in there and still have it read well I see no reason why not, but I wouldn’t add another keyword just for the sake of getting another one in there.

    Do you think placing an image higher on the page helps or are you referring more to the use of keywords in the text surrounding the image?

  2. You know I’m not really sure how search engines would see the londesc attribute. It might make for a good test. I would think they would see it similar to the alt attribute, but it’s possible they would put less weight on it.

    I generally don’t use them, because a few words is usually enough to describe the image. They work the same way as the alt attribute. The main difference is you’ll use more text in the logdesc. I should probably know more about the differences, but I don’t use longdesc much.

    I always prefer to thing of image attributes as an accessibility thing. They’re there for someone who can’t see the image. I’ve chatted with a couple of people who are blind and asked them how they wanted the attributes treated and the response was to describe the image. Even though they couldn’t see it they wanted to know what was in the image.

    That’s interesting about filling up the space. I suppose you could incorporate the longdesc text into your design, though keep in mind most people who are making use of londesc aren’t going to be seeing the text either.

  3. How is the longdesc attribute used? By browsers, more than search engines … I’ve always thought it was appropriate to put as much text as will fit into the space given to the image. If it doesn’t load, or someone is using dial up, that seems like a reasonable maximum amount of text … especially people on slow connections will have the opportunity to decide whether or not to wait for the image to load.

  4. Man Steve…I really had to strain to get the addition right for the submission!

    “Please multiply 4.34345 x 8.88237??

    *phew*

    Anyway, I’ve had more success n Google images with short descriptions than long but maybe Forrest has more experience in tis than I do. I have also heard alt attributes carry more weight with google when the image is also a link…

  5. Dave I’m not sure why the math thing keeps failing. I think ever since I added the spam karma II plugin the did you pass math plugin acts all funky. I still end up getting an email of the post and many’s the time I’ve just manually added them after.

    By the way where’s the 700 word essay you promised?

    I think when it comes to a link Google will treat the alt text similarly to how they would anchor text so it’s good idea to get that alt attribute in there. I’m not really sure about the shorter descriptions vs. longer descriptions. I hope I didn’t start something with the longdesc attribute. I meant it more as an accessibility thing than as an seo thing.

  6. You know, I’ve never used the alt attribute for seo. I’ve heard many times that it’s treated a lot like normal anchor text in image links, although I haven’t changed my navigation to use images with alt text. A site could look much better if that’s true…

    I’ll have to start experimenting with the longdesc attribute, but if it’s not displayed until the image has downloaded, or as mouseover text … it’s really not that useful. At least from the sounds of it, the only benefit could really be any minor seo gain. I’d rather go on making long alts, what seems appropriate in context, as long as it’s safe to assume the engines won’t punish me.

    Just for plain usability reasons, it seems like a good idea to be verbose ( stream pouring down the side of a mountain vs just a mountain ) and to try to use any particular word as little as possible. Which is sort of the opposite of keyword stuffing.

  7. I don’t think you have to do too much seo wise with the alt text. All I ever do is write a quick line describing the image. If I can get a keyword in great, but I’m writing the description for some who won’t see the image and not for search engines.

    Here’s what I just grabbed about the longdesc attribute from the w3c:

    “This attribute specifies a link to a long description of the image. This description should supplement the short description provided using the alt attribute. When the image has an associated image map, this attribute should provide information about the image map’s contents. This is particularly important for server-side image maps. Since an IMG element may be within the content of an A element, the user agent’s mechanism in the user interface for accessing the “longdesc” resource of the former must be different than the mechanism for accessing the href resource of the latter.”

    It sounds like they want you to use it more in conjunction with the alt attribute rather than instead of it. I doubt there’s much seo in the longdesc in general, though it would be something interesting to play around with.

    Your example is exactly how I would use the alt text. I think descriptive is good and the couple or three blind people I’ve asked have said they want the description.

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