The image lets you know what the artical is talking about, while the caption is explaining the image for you to make the connection. I hope this helps.
Images and captions can help explain the main idea by showing the meaning behind the image or even showing what the image is of or even when it was taken. They help you understand the main idea also by giving you an example that you can see rather than just read.
The noun or noun phrase that's modified by the prepositional phrase is: The butterfly net because the prepositional phrase is modifying (describing) the net, not Kristy
