There are a couple ways to go about creating image captions. One way is to use the
<small> html element inside a post. Just type out something under your image like this:
<small>This is a caption</small>
Here is an example of it in a Write.as post from @scott :
Another way is to simply use italics under an image. Here’s an example from @Melyanna :
If you want to make the caption centered and smaller, you can add the following HTML to your post under the image:
<div style="text-align:center;"><small>This is a caption</small></div>
Hope that helps & let me know if you need anything else.