You can add an Alt-Tag to an image if you use our 'Images in text' feature.
To add an image:
1.) Select a text box that you would like to add your image to.
2.) Click the edit control or double the text to edit the text, you will then see the text editing bar appear at the top of your page.
3.) From the text editing bar select the 'Images' option.
4.) Upload an image or choose an image from your library.
5.) Once you have selected an image it will display in your text box, you can see an image of a dog in this example:
6.) Click the image and you will see the option to edit (text must be editable at this point):
7.) In the 'Title' field add the text that you would like to use for your alt tag description and press save.
You will be able to see the alt text if you inspect this element with developer tools: