It always amazes me how many people overlook this simple step. Search engines can only read text so by adding so-called alt-text to your images you increase your changes of being found via your photos. Plus, Google likes websites that use media effectively, such as photos and videos. Also, visual search engines like Pinterest will pick up and use image descriptions so you want to always make sure to include them with your photos.
When deciding on your image text don't just put your business name under every photo (Google does not like this kind of duplication) - instead write a short description that is relevant to the topic of the page or the blog post where you are using it, and append that with your business name, see example above.
How to add alt-text to images in Squarespace:
When you insert an image block you can add the alt-text in the Caption Field below the image. Even if you don’t want to display a caption, add the text anyway and then choose Do Not Display Caption from the drop down list inside the image block.
This is the gallery that you add as a page in your navigation menu. Once you have uploaded the images hover the mouse over the photo you want to update and click on the wheel, then enter your alt-text into the Title Field. You typically add the content of these gallery pages via a Gallery or Summary Block and you can choose in the Design settings of these blocks whether you want to show or hide the page titles.
A gallery block sources its content either from a Gallery Page (see above) or you can upload photos directly into the block. In the first scenario you have to add the image titles via the Page Gallery, or if you upload photos straight into the block then you simply hover over the little cog wheel on the image and add the alt-text in the Image Title field, as shown in the screenshots below. If you don’t want to see the titles on the page you can disable them in the Design Tab of the gallery block.
Open the Edit window for the product and hover your mouse over the image and click on the wheel, then enter the alt-text into the Image Metadata Field.
Cover Page Images
Same again, add alt-text to any images you use on your cover page.