Online indexes can lead you to an image of a record with a quick search–if you are lucky enough that names are spelled and indexed correctly. Make certain the “next image” isn’t part of the item you located. Census records may be split over two pages, draft cards are often images of the front and back of the card, death certificates sometimes contain “supplements” directly after the original document.
Always look at the next image or two in any online set of images to make certain you’ve got it all–and look forward too as well.
You’ll never know until you look.