This is how a picture can be added.  Note how cleaner designs (in my opinion, at least) center photos and left align text.  Alt text is always preferred to a caption, as this has the extra effect of making the page more accessible for those who use screen readers.  When a second image must be added, remember to center align it, like this:

There’s really no need to edit the CSS data for the picture, as the WYSIWYG editor does a fine job of automating that process.