how can i make a picture into a pixelated tile?

[GYM28]

remember in mario paint how you could make stamps using pixels?
well i'm trying to make a tile pattern outta pixelated photos of paintings.
i tried resolution changes but then the image size obviously gets too small to work with.
sorry if i'm not clear enough on what my goal is.
thanks in advance.

[mozartdminor]

Not sure exactly what you're looking for because I've never used mario paint. I got a blocky/pixelated image pretty easily like this.

1) image->adjustments->posterize (slider: 10)
2) filter->texture->patchwork (sliders: adjust to taste, I used 9, and 8)
optional step:
3) image->adjustments->brightness contrast (sliders: adjust to taste I used -50, 20)

Result

Original