Instagram finally launched on Windows Phone this morning, making the popular photo-sharing app available on every major mobile platform. But while it's on iOS, Android, and Windows Phone, the app differs significantly from platform to platform -- particularly on the latter. Windows Phone has positioned itself as a unique mobile OS with a strikingly different look and navigation features compared to other major platforms. Most apps on Windows Phone look and behave significantly differently than on iOS or Android, and Instagram is no exception.

Navigation On iOS (always pictured on the left) and Android (center), the main navigation tabs -- your feed, Explore, the camera button, your notifications, and your profile -- are spread across the bottom of the screen. On Windows Phone (right), everything but the camera button is located in the upper right of the app, next to the Instagram logo. The button is centered at the bottom of the screen with a search and refresh button on either side. On iOS and Android, the refresh button is located in the upper righthand corner. Instagram's logo is centered on the feed tab in iOS, and left aligned on Windows Phone and Android. The Feed Scrolling through the stream of filtered photos uploaded by the people you follow, the experience is fairly similar across platforms. Your friend's smiling circular avatar, name, and the time since they posted the photo are followed by a square image that takes up the width of your phone's display. Beneath, comments and likes. On iOS, the "..." button that gives you the option to report a photo as inappropriate or share the URL also has the convenient option to tweet the photo. You flick upwards to go back in time in your feed. On Android and Windows Phone, the Instagram logo is persistent across the top of the screen as you scroll down.

Taking Photos Despite initial reports, the Instagram app for Windows Phone does let you take photos directly in the app -- it's just an extra step. In general, the photo taking and sharing experience on Windows Phone is a bit more disjointed than on the other platforms. When you click the camera button at the bottom of the screen, it gives you the option to select a photo from the camera roll. There's another camera button at the bottom of that screen you can tap to actually take a photo. The app does not let you take videos like it does on Android and iOS. On the latter, cropping is accomplished in the same step as selecting the photo. On Windows Phone, you select the image and cropping is an extra step. From there, on all three platforms, you've got your editing and filtering options. When your photo is adjusted to your liking, the next screen on iOS and Android looks nearly identical, with space for adding a caption, tagging people, adding to your photo map, and sharing to different social networks. On Windows Phone, you can't tag people or add to your photo map. You can add a location to photos, though. You finish off the process by tapping a checkmark at the bottom of the screen on Windows Phone, or the green share button in the upper right of iOS, or the green checkmark in the upper right of the Android screen.

Explore In the Explore tab, a search field sits at the top of the screen in iOS and Windows Phone. The latter also features that search button next to the camera button at the bottom of the screen. Android features a search button in the upper right that opens a separate page for Instagram searches.

Notifications As for your notifications tab, iOS and Android let you distinguish between a list of updates that just related to your own post ("News" on iOS and "You" on Android), or what the people you're following are up to ("Following"). Windows Phone only displays notifications pertaining to you, with the the Following News option hidden in the options button in the lower righthand corner -- easy to miss.