I want to take some stock art (can be of any dimension) and make it look pixelated, kind of like old Mario Brothers video games circa the 80's. Part of the image manipulation would require scaling down.
This is what I'm starting with.
Is there a filter or some Photoshop steps that I can use to make this effect?
I tried essentially using the "Pixelate" filter but that creates transitions pixels between color edges. I also just tried to reduce the size of the image to 40 x 35 pixels and this is what I see.
How do I get the crisp, full color pixels like the Mario Brothers icons.
Here is a somewhat easy method to convert full size images to pixel graphics.
To begin, go to Image -> Image Size. Change the Resample method to Nearest Neighbor, this will keep the hard edges. You can zoom into the preview on the left to get a good idea of what your end result will look like. You can see I'm at 500% in this example. Next set the width / height to your preferred size and hit OK.
This next step is optional
Go back to image size and increase the size of your image to your required specs. Make sure to keep Nearest Neighbor on. Press OK when done.
Here is what your final result will look like (Depending on how much you downsized the original.)
When you are working with so few pixels you have to make every pixel count. I doubt an automated scaler will achieve that with satisfactory quality.
My advice would be to downscale to the size required as normal (or possibly using a nearest-neighbour option), then zoom in, turn on the grid and go over your image pixel by pixel cleaning it up. To enhance the retro look you should also work with a limited palette of strong colors.