You can select them from within BBEdit or drag them in from the desktop. Either way, BBEdit wraps each image in its own image tag, and populates the height, width, and alt attributes automatically (it uses the file name for the alt attribute, so you might want to change those).
There is an important different between dragging images in from the project window sidebar, and dragging them in from the Finder. If you drag them in from the project window sidebar, the images will appear on the page in reverse alphabetical order. If you drag them in from the Finder, the images will be in alphabetical order.