To a make a collage on the computer depends on the application your using. For instance Photoshop : 1) Specify the size that you want the collage to be, 2)Click on ‘File’ and ‘Place.’ Locate your picture and click on it then choose ‘Place’ again. 3) Resize your picture by holding down the left mouse button and dragging it inwards.4)Crop out any unnecessary space on your picture by clicking on the cropping tool on the toolbar 5) Move the picture where you want it on the canvas by clicking the move tool. 6)Place a new picture on the collage by clicking on ‘File’ and ‘Place.’ Select your picture then click ‘Place’ again. Repeat Steps 2 through 5 to resize and reposition your picture in the Photoshop collage 7) Finally, Right-click on your pictures and choose its layer to move it around after placing additional pictures. When you are done placing photos then click on ‘Layer’ and ‘Flatten Image’ to reduce the file size. Save your file as a .tiff or .psd to retain it’s quality.