Choose the pattern that you want to place on the boxer shorts.
Scan the picture onto your computer using a scanner or upload it from a disk or camera with your USB cord. If you chose a picture from an online source, save the image in your picture file.
Reverse the image using a program, such as Microsoft Paint, so that the image is a printable image file. To do this, open the picture in Paint after you have saved it to your computer with an image extension (.jpg, .png,etc.) and select "flip/rotate" from the "Image" option in the menu.
Create the print all over by copying and pasting the reversed image across the entire page in Paint. If you are using a different software, you may have the option to automate this step with a simple selection from the menu that allows you to repeat the image. Some print-page set-ups have the option to repeat the image to cover the entire page.
Print this pattern on transfer paper using your laser or inkjet printer. If you prefer to test the printer first, print the pattern on a plain piece of paper to ensure that it comes out as a reverse image.
Cut around the pattern, leaving a border on all sides that is 1/4-inch wide.
Wash and dry your boxer shorts.
Iron the boxer shorts to smooth out any wrinkles. If this step is skipped, you run the risk of having incomplete or blotchy prints.
Place the iron-on transfer face down on your boxer shorts and iron on a flat surface. You may also test the transfer on a piece of scrap fabric to ensure that the print comes off the paper as you envisioned. If you decide to perform a test, you will need to print out another piece of printed transfer paper for the final project.
Lift one corner of the transfer and carefully peel it away from the boxer shorts.