How best to implement this puzzle app for android
<p>Let's say I have a pair of two images .pngs being displayed in an Android App. The puzzle for the user is to identify the elements in Picture 1 that are missing from Picture 2 by touching the elements in Picture 1. Once all the elements in Picture 1 missing in Picture 2 are identified the App moves on to the next pair of images. </p>

<p>I could store these images in SD Card or populate the ImageView in the App realtime from the server. I think since there are going to be a large number of images it would be wise not to store them on the device storage itself.</p>

<p>I think it would be nice to have these image pairs show up like a carousel view so that both the images are not visible at once but the user moves back and forth between them to identify the differences.</p>

<p>The thing that I am still trying to figure out is that what would be the best way to validate the user selection of differences for a pair of pictures.</p>

<p>Any idea or help is much appreciated.</p>

<p>Example images could be pic1.png and pic2.png below</p>

<p><img src="http://i.stack.imgur.com/sLJ1Z.jpg" alt="Door Knob missing"></p>

<p><img src="http://i.stack.imgur.com/UQ6sX.jpg" alt="Door Knob present"></p>
