The tipster who provided the images to AppleInsider claimed they are from an "earlier build of iOS 7 beta," and suggested the look may have changed "slightly" since then. They are shown running on an iPhone 5 with a Lightning cable attached.
The images show Apple's iconic "slide to unlock" user interface element replaced with a circular button that looks akin to the current iOS slider volume control slider. To the right of that space is an icon that cannot be clearly seen, but in iOS 6 it is the quick camera access button.
A final image shows a lock screen with passcode enabled, featuring circles where the four digits would display once entered. In an un-Apple design choice, users are prompted in all capital letters to "ENTER PASSCODE."
AppleInsider has no reason to believe these images are an accurate representation of iOS 7, and has published them on its backpage for entertainment and discussion purposes only. The real iOS 7 is expected to be unveiled in less than a week, at Apple's Worldwide Developers Conference keynote next Monday.