It’s surprisingly simple to capture a long web page in a single screenshot on your iPhone or iPad, and edit it to hold just the information you want.
In fact, though, your “screenshot” taken on an iPhone also captures the entire page of the website, no matter how long it is. You have to then say that you want the full screen image, but when you do, you can also easily edit the screenshot after it is taken to trim it to any section you really want.