HTML5 Image Insert
The big advantage of inserting an image via an HTML5 figure element is that the the image and its figcaption are seen as being related to each other by the search engine spiders. This is obviously better than just depending on the alt attribute and a caption added via a text box.
A text box "caption" is meaningless to the search engine spiders as it just appears to them as an unrelated chunk of text. In most cases, a caption will create more interest with visitors. A lot of people who create websites seem to think that, just because they know what the image is about, the rest of us should too.
The widget settings are shown to the right...
Choose the image, set its size using the drag handles or the Metrics inspector and enter both the alt text and the descriptive caption.
If a border is required, set the padding and add a box shadow if needed.
Enter the font family name, check the box if it is Google hosted and choose a suitable web safe fallback font.
Set the font size, color and text align.
The vertical position of the caption can be adjusted to suit the amount of padding (border) that has been applied.