Open a New Image. (File > New)
Activate the Rectangle Tool and choose the Draw Square
mode. Check the box marked Create on Vector. Slide mounts typically have
rounded corners. For this example, I changed both the Horizontal and Vertical
Radius to 10.00.
Be sure your foreground or stroke color is transparent and
you have chosen a color for the background or fill.
Draw your square, apply it (by clicking the checkmark)
and
then center the square by using the Object Selection Tool)
and clicking Center
in Canvas.)
You will now create the slide mount’s opening. Change the
background color to something that contrasts and is easy to see. In the
example, I have used black.
Create a new Vector Layer (Layers > New Vector Layer > OK)
Reactivate the Rectangle Tool and choose the Draw Rectangle
mode. (At this point, you may need to re-apply the previous square shape by
clicking the checkmark again 
}.
Change both the Horizontal and Vertical Radius values to
0.00.
Draw a rectangle in the contrasting color on the new vector
layer and center the rectangle vertically.
Be sure the Vector Layer containing the slide mount’s
opening is active (in this case, the black rectangle.)
Go to Selections > From Vector Object. The black rectangle
should now be selected.
Go to Layers > Convert to Raster Layer. This changes the
Vector Layer with the black rectangle into a Raster Layer.
Without deselecting the rectangle, hit your delete button
and delete the black rectangle. DO NOT DESELECT AFTER DELETING THE RECTANGLE.
Go to your Layers palette and make sure the Vector layer
containing the slide mount is active. Again, DO NOT DESELECT.
Go to Layers > Convert to Raster Layer. This changes the
Vector layer with the purple slide mount into a Raster layer.
Without deselecting the rectangle, hit your delete button
and delete the middle section of the slide mount. This creates the opening of
your slide mount.
Deselect the opening. (Selections > Select None)
With the Magic Wand Tool select the slide mount. 
Apply a slight inner bevel to give the slide mount
dimension. (Effects > 3D Effects > Inner Bevel)
Experiment with the different values. In the example, I
used the following settings:
You can now place a photo under the slide mount. Remember
to add a drop shadow. (Effects > 3D Effects > Drop Shadow)
