Did you examine the HTML? It's a bit tricky, and unfortunately ends up being dependent upon users to have their browser font settings close to what is expected, but it can nonetheless be useful for adjusting the captions on pictures.
On a related note, another alterative to 'italicizing' pictures is to resize them. Note that resizing a picture using the image properties will not affect loading speed (and should thus not be used as an alternative to generating real thumbnails), but if one is 'quoting' a picture that has already appeared on a thread, load time is not a factor.
To avoid using excessive vertical space, it can be useful to attach an 'align' property to the image. Most commonly, align=right as in this example. Notice that the text will conveniently wrap around the picture as appropriate.
The image align and table align properties can be very useful, although strange things can happen if you use too many of them in overly-close proximity. I don't know of any browsers that will crash if such things are attempted, but the result can sometimes end up being an indecipherable mess. Nonetheless, the properties can allow for pages that automatically adjust their formatting based upon screen size. Check out A Bird in a Barren Cage and play around with screen dimensions and font size. You'll notice the page can take on a few different arrangements even though it uses no scripting.