I'll show you the fastest and easiest way to create a glass-shatter effect without "leaving" Photoshop.
1. The idea of the above shatter-effect is that the window was shattered, but you could still see some reflections of the outside landscape through the window.
Grab yourself a nice stock photo, I used this one:
2. Create a new layer and fill it with black. Send it to back (behind the image layer). Change the Opacity of your photo to a low value (10%) and press CTRL+J to duplicate it. On this top layer change the opacity back to 100%.
3. Press CTRL+U to open the HUE/SATURATION panel and change Saturation to "-30" and Lightness to "+30".
Using the Polygonal Lasso Tool (L) select a region from the photo and press CTRL+J having your photo layer selected to copy this region onto a new layer. Now, go back to your 100% opacity photo and ctrl+click the layer created before and press delete. The photo will look the same, but you'll have two pieces that form the photo.
Here's a screenshot showing how I've selected the regions and copied them:
Note that the image above is formed by all the 6 pieces showed at the same time (I've actually added a red stroke to show you their shapes).
4. Now we have to move them a little. Select each layer containing the photo and press CTRL+T to transform it. Rotate them until you get something like this:
5. Let's stylize the pieces, double-click next to one layer's name to open it's layer style panel and use this settings:
6.Now you have that style applied on one layer.Right click this layer in the Layers panel and press "Copy Layer Style".To apply that on all the pieces simply go to the Layers panel and click the first layer then shift+click the last layer containing a piece of your photo. Right click on one of the selected layers and choose Paste Layer Style.
7. To make this design look even better you can create a new layer (SHIFT+CTRL+N) , go to Image->Apply Image and add Filter->Render->Lens Flare. You can place multiple lens flares. I've marked with red circles the spots where I've placed lens flares.
That's all :).
If there's anything unclear feel free to post a comment below.