Photoshop is an effective program to edit and create artistic effects to your photos. An oval frame can make your photo appear personalised, like in a locket. You can achieve this effect by using the "Clipping Mask" tool.
Open your image and make sure it is editable by dragging and dropping the locked layer over the "New Layer" icon in the "Layers" panel.
Create a new layer. Choose the "Shapes Tool" and click "Fix Pixels" icon in the shapes toolbar. Draw an oval around your subject. Your subject will now be blocked by the oval.
In the "Layers" panel, move the layer with the oval underneath your image.
Still working in the "Layers" panel, hold down the "alt" key and click between the two layers. This will create a clipping mask that conforms your image to the oval shape you just drew.
On the bottom of the "Layers" panel, click on the "Add layer style" icon. Choose "Blending options."
In the pop-up window, choose "Stroke." You can create an outline of your oval using solid colour, gradient or pattern. Adjust to your liking.