Yovo (free) is an interesting app developed by ContentGuard, a leading company in the field of protecting electronic communications.
With Yovo, you can pick a photo on your iOS device and send it to someone. They see the image in their mail or in text messages, but the photo is blurred, something that is done within the Yovo app before you send the photo.
Alongside the blurred photo, the recipient gets a URL that they click on to can see the photo without any blur. Yovo offers the ability to set a timeout on the photo, anywhere from one minute to 24 hours. After that, the URL ceases to deliver the photo.
The app also works with Facebook and Twitter, and you can delete your photo at any time. The app also tries to thwart screen captures, by displaying a vertical grid obscuring a lot of the photo.
It's pretty easy to use Yovo, and the app does have built-in help. I have no doubt the image is secure, and I tried the time-out function and it worked as advertised. One big weakness is that the URLs won't display on a computer, as this is meant to be for mobile to mobile communications only. The Yovo folks told me their expertise is in mobile, and they think most people are exchanging photos on mobile devices. It seems like a pretty serious limitation the way I exchange photos, and I can't predict if someone will get my mail on a mobile device.
Other than that, the app works as stated, however I don't think the protection against screen grabs mentioned above is effective. The app calls this feature D-Fence -- which puts a series of vertical lines in front of the photo -- and I could see plenty of the D-Fenced photo through the lines, so I don't think it mattered if I used the feature or not.
Yovo seems to be targeting the same customer of ephemeral messaging as Snapchat, another free iOS app. With Snapchat you take a photo or video, add a caption, and it disappears from the recipients screen after it is viewed. The recipient can capture the photo by taking a screenshot, which pretty much defeats the purpose.
Yovo requires iOS 7 or later. It's not universal, but should run on any iOS device.