Mary,
Image->Resize->Canvas Size
Enter a new height value, as desired. Click the top center anchor arrow so that the new canvas will be added to the bottom, and centered.
When you click OK, the new space will be added, filled with your background color.
Byron
Beth,
I agree, completely! 😉
Byron
You can do that through Image>Resize>Canvas Size. Size your photo, and then expand the canvas size enough to give you room for the caption. There’s also a place in that resize window that lets you choose the portion of the canvas in which you want your photo "anchored." It defaults to centering the image on the enlarged canvas, so you’ll want to change that to the "top center" if you want the caption underneath. It’s hard to explain but will be pretty obvious once you look at it.
Yeh, me too! We must have been typing at the same time, huh, and I’m just faster on the Post button? 🙂