This technique lets us create the effect of a photo painted onto a canvas, and we'll achieve this in a very flexible way that can easily be edited.
Press-and-hold the Option key (PC: Alt key) and double-click on the Background layer in the Layers palette (to unlock the layer so we can add a layer mask to it).
Press-and-hold the Option key (PC: Alt key) again, and click on the Add Layer Mask icon at the bottom of the Layers palette (this will add a layer mask filled with black, so all you will see at this point is the layer transparency checkerboard).
Now we'll add a new layer below our photo by pressing-and-holding the Command key (PC: Control key) and clicking on the Create a New Layer icon at the bottom of the Layers palette. Fill this new layer with white by pressing D to set your Foreground and Background to their default colors, and then pressing Command-Delete (PC: Control-Backspace).
With the Brush tool (B) selected, we need to change to some of the more unusual brushes. Click on the Brush thumbnail in the Options Bar and from the Brush Picker's flyout menu, choose Thick Heavy Brushes from the list of built-in brushes. Click OK to temporarily replace the default brushes (you can always choose Reset Brushes from the flyout menu to return to the default set).
Choose one of the new brushes in your Brush Picker, press X to set your Foreground color to white, click on the layer mask thumbnail in the Layers palette, and paint to reveal the original photo as shown here. Of course, you can experiment with different brush shapes, sizes, and opacities. In the second example, I painted the top and bottom edges with a different brush from the Thick Heavy Brushes set.
Here's another variation where I changed the underlying layer from white to black and applied the Texturizer filter (go to Filter>Texture>Texturizer, and choose Canvas from the Texture pop-up menu) to the layer mask.