Smart Object
In the Layers panel, go to the layer options in the top/right corner… and Convert to Smart Object.
You should then see a little icon on your layer thumbnail like this…
Filter: Mosaic
Make sure the Photo layer is active/selected. Then go to Filter > Pixelate > Mosaic. In the window that pops up, set it to “10”. Then click OK.
Now it looks pixelated like this…
Since we applied a Filter to a smart object, you should see it here…
Adjustment Layer
At the bottom of the Layers panel, click on this button to add an adjustment layer…
Choose Pattern…
You will see a pop up window, probably with dots as the default pattern. Change Scale to 10 (so it’s the same size as the mosaic).
Your document looks like this…
… and your Layers panel looks like this…
Now change the blend mode for the adjustment layer to Multiply.
And you’ll have this.
Own Photo
Now try this with your own photo. Go into the Smart Object (double-click on the layer thumbnail)…
Paste a photo of your choice and resize (CTRL+T) to fill/cover the original photo. When you’re happy with the size/position, hit [Enter] to apply the transformation.
You have an * when a file isn’t saved. Save the file (CTRL+S) and you should not see the * anymore.
Go back to your working file.
Now you’ll see an updated effect.
You can go back and try different sizes for the Mosaic and the Pattern…
