To add alt text to any image in your design, click on the Image layer you'd like to add a link to, then click the Settings button in the plugin header, and type your alt text into the Alt Text input field.

This will set the alt attribute of your <img> tag in the HTML when it's exported from Emailify.

You can apply settings in bulk by opening Settings, then selecting multiple Emailify layers of the same type in Figma. Any setting you change will be applied to all selected layers.