Fakin' It - Polaroid Transfers That Look Real

Step 14 Using The Border : Matching Size

Now we're going to try to match your border to the image size your camera takes, however we want to make it just a little bigger so that the border isn't encroaching on your photo too much.
Open your Polaroid transfer border and select Image Size front he Image menu at the top of the screen. Determining the right size is tricky and may take a few attempts, start with your the dimensions from step 1 then add an extra 10% to the width and about 6% to the height. Make sure you uncheck "Constrain Proportions" box. Paste your camera image into the border and make sure the border overlaps it but that the image doesn't extend past the border. If it doesn't just "undo" back to the re size and try again. For me a good number worked out to be roughly 4120x2860 which is where I got the 10% and 6% from. Once you have it right, delete the image layer leaving only the borders and the background, change the background colour back to white, and save it as a psd file.