The bigger picture
First, let’s zoom out a little bit and really get the context of what we’re talking about. We’re talking about an SEO component—and keep in mind that SEO is only one piece of digital marketing.
Adding alt attributes is very specifically a search engine optimization tactic. However, there are a lot of other things you can be doing in order to drive traffic and customers to your website.
Even more, within SEO, image alt text optimization is only one piece of the entire on-page optimization process. So just getting this right, or just getting this wrong, is not going to make or break you either way.
To get a bigger picture of SEO and how to run a comprehensive audit, check out our SEO checklist.
Let’s move on to image alt text (or alternative text) and file names now.
How alt text works
Search engines are not humans, right? They do not view or see images the way that we do.
We, as SEOs and digital marketers, have to do something to help search engines a little bit (give them some hints on what images are about.)
One way we help search engines “see” images is by naming them properly with image filenames and alt text. These function as an image description that helps crawlers “see” the pictures on your site.
Furthermore, this is also used for accessibility: visually impaired or blind users use special browsers that read images to them and image alt text and our file names can be helpful for that.
When you’re writing your alt text, you should generally stay within the 125 character count. Thus, you can populate that as much as you’d like, as long as it’s reasonable.
It’s important not to forget about the filename (this happens a lot, believe me). A lot of people upload a file with a very general name (e.g. “home-page-graphic-6.png”)—and that’s not good. You can (and should) be much more descriptive than that – both for screen reader users and for search engines as well.
Also, please keep in mind that this tactic is prone to over-optimization. I know this because I used to do it.
When people first get into search engine optimization, they get very excited about this. They go through the entire checklist and they say “OK, there are all the things I need to do to rank higher in Google, I’m really excited about this.”
Eventually, they get to the image optimization part and they look at their images and then they just…overdo it.
They stuff it the image optimization with too many keywords and they just end up with a non descriptive alt text. You should try to avoid making this mistake. Use relevant keywords and try not to overdo them.
Let’s look at a couple of examples.
Below, you will see an image from Zappos. The file name is “mens-boat-shoe.jpeg”. Remember, whenever you have spaces in your filenames, you want to use hyphens, not underscores.