In this tutorial I will show you how to add a stylish page curl to the corner of your image. To start, lets get an image that we can add the page curl to. Here is the one I used.

Take your polygon lasso tool, and select the corner that you want to curl. Make a selection similar to mine. Once you have it selected, press delete to remove that portion of the image.

Click on your gradient tool, and choose a linear gradient. Change the colors to match the image you are curling. You want your page to look like it is bulging towards you, so place the lightest part of the gradient towards the center. Place your gradient so that the lines run parallel to the incline of the page curl. Refer to the example below.

Now we are going to move this into the correct position. Choose Modify > Transform > Free Transform

Rotate your gradient and position it in line with the deleted portion of the image.

Now lets give your image some depth. Add a drop shadow by clicking + sign in your properties tab. Change the direction of the light source so that shadow displays on your image and not the deleted space.

Your done! Here is how it might look with some text, and a darker background.