These options can be found in the Image Editor. Mouse over an image and click on the small pencil that will appear. Choose the image editor button and a new window will open where the image size, link, title and alt tags can be set.
The value of width and height should be the same with the real values of the image chosen. If you set a higher value the image may stretch and look bad.
The value inserted in the ‘Alt Tag’ will appear inside the image container when the image can not be displayed. Alternate text is very helpful in case images on a page cannot be found, or your email didn’t yet load properly.
The text entered inside the ‘Title Tag’ will be displayed in a popup when a user takes their mouse over to that image.
‘Link url’ is used to add a link to an image. Just insert the url address of the page you want to be redirected to.
Save it to apply the changes.