There are a lot of pretenders to the Instagram throne, but the photo-sharing service is so popular that any new photo-sharing app had better bring something new to the table, like Vine's 6-second videos. Moju might be the next Vine, with its motion photos that act like remote-controlled GIFs.

Moju, available only for iPhone right now, straddles the line between video and photos, much as the animated image format GIFs do. But you can control which frames of a Moju motion photo you view, just by twisting your iPhone.

Moju is an image-sharing app and network much like an early, bare-bones Instagram, with standard sharing, filters, commenting, exploring, posting, "liking" and profile features.

But that part of the app is standard and boring. What sets Moju apart is that each Moju image contains up to 24 frames, or separate stills, that can include any number of interesting effects, which are controlled using the motion-sensing hardware in the iPhone. Just twisting the iPhone back and forth vertically moves the Moju image back and forth through the frames, animating motion shots, giving you a panoramic view as if you were actually there turning your head left to right, or otherwise controlling creative images Moju users have come up with.

"Photos are too concise; video is not concise enough," as Moju co-founder and CEO Mok Oh told The Next Web, seems to be the motto of Moju. "The twisting motion in consuming the content has a visceral effect on the viewer. I can control this. I can look at the frames I want. I can go fast or slow. So that control is simple but powerful."

The reality of the app can be a little vertigo-inducing, since every Moju in your timeline will shift through its frames whenever you move your iPhone. It's a great app to train yourself to keep your phone stationary when you don't want to animate the images. But it really is visceral, and addicting.

And it's easy. Looking at a Moju image, you might think getting the image capture down would take a lot of practice, but it's really simple. When you're taking a Moju image, 24 distinct dots will appear right above the capture button. Moju doesn't require you to capture the maximum number of frames, though.

You can hold the capture button down to take a smooth video (turning on the "ghost" option will smooth between frames even more), or you can take individual frames and Moju will put them together for you. Or you can do a mix. A simple "back" button will undo the latest frames you take, or you can scrap the whole thing and start over. Moju gives you the option of 12 filters, though they are not Instagram-quality -- and they're mostly unnecessary.

After you've captured and captioned the Moju (this may become the shorthand word for the multiframe, controllable GIF-type images Moju has invented), Moju gives you the option to post to Facebook, Twitter, share via URL or keep it private.

Already, Moju's relatively few users are experimenting with cool visuals, going beyond time-lapse and panorama. Some have made magic trick effects using the frame-by-frame mode, and others have created 3D holographic effects by doing a reverse-panorama on a single object. Check out Moju's page for some examples, which allow you to animate the images with mouseover movement.

Moju, like Vine, has a lot of interesting, creative images and visual storytelling devices that will probably come out of both its limits and its unique abilities.

Tap That App? Definitely. It's interesting, unique and free.