Today I worked in photoshop on a poster project of Mona Lisa in lego form.
I started by creating a new document that is 8.5 x 11. Then I used the rectangular marquee tool to make a square, then I right clicked on the selection and chose stroke in the pop out menu. Then I used the elliptical marquee tool to make a circle inside of the square. Then I double clocked on the circle and went to the blending options panel and gave the circle a drop shadow. Then I opened the lego logo image and used the move tool to drag it into the new document. Then I went to the image menu, then to adjustments, then to hue/saturation and changed the saturation to -90. Then I right clicked on the upper most layer and chose merge visible in the pop out menu. Then I pressed command-t to shrink the lego piece to the right size, then used the move tool while holding the option key to duplicate the layer until the legos covered the document. Then I right clicked on the top layer of the layers panel and chose merge visible in the pop out menu . Then I opened the mona lisa image and used the move tool to drag it into the background document. Then I moved the monalisa layer behind the other layers.
Then I created a new layer on top of the other layers. In that new layer I used the rectangular marquee tool to select around individual legos, Then I used the eyedropper tool to select color from behind the lego pieces (in the mona lisa layer). Then I right clicked on the selection and chose fill with forground color in the pop out menu. Then I repeated these steps to give each logo peice a solid color.