ADD IMAGE TITLES AND CAPTIONS
You can create and edit your image titles and captions (i.e. Alt text) within the Gallery.
Double-click an image thumbnail to launch the Image Info Editor.
Insert the Title and Caption and Keywords in the provided fields. This information is also used in conjunction with our SEO Image Pages feature.
If you would like to display captions on your site so that your visitors can view them, check your Image Info settings in the Design [tab] > Gallery > Slideshow Options > Info Panel to enable its visibility.
Text entered within the Captions field will also be displayed within the HTML source code Alt text for that image on your website. Alt tag information is helpful to search engines to associate images to your website.