Writing ALT tags for SEO
Part 1: What are ALT tags?
"ALT tag" (or "ALT text") is a short piece of text written for each image of a website. The basic purpose of an ALT tag is to provide text that will be read aloud by a special screen reader for visitors who are vision impaired. However, ALT tags also communicate to search engines about the contents of the image, and thereby the contents of your website. For example, when you use Google images, it’s the ALT tag that helps an image show up in your search.
Note that you obvious won't be able to describe every single detail of the image, so you'll want to focus on what's most relevant within the context of the page.
Part 2: Writing ALT tags
How to technically add ALT tags to images on your site
If you are working with myself or another web designer, chances are they will do the technical part for you. If you are doing this yourself, the procedure will depend on which website platform you use. Here are articles how to add ALT tags on Squarespace and Wordpress.
Before writing ALT tags
Identify what key words you'd like to be found for. Typically an interior designer will want the words "interior design" and the name of their market, such as "Boston." If you as a designer happen to specialize in a particular type of design such as kitchens or bathrooms, you may want to include those words as well.
Part 3: tips for writing ALT tags
TIP 1: DESCRIBE THE IMAGE AS SPECIFICALLY AS POSSIBLE
First and foremost, ALT tags are meant to provide text explanations of images for users who are unable to see them.
TIP 2: KEEP THE TAG SHORT AND MEANINGFUL
This lends more weight to each word you use. It can be tempting to write long sentences in order to stuff your ALT tag with key words, but search engines are smart and may penalize you for key word stuffing. According to MOZ (the leading company on SEO) good rule of thumb is to limit to 125 characters.
TIP 3: DON’T INCLUDE “IMAGE OF” OR “PICTURE OF” IN YOUR ALT TAG
It's already assumed your alt tag is referring to an image, so there's no need to specify it.