To create a mock up image for a product, select the product on our website. Click on Upload your own image. Once you have chosen your image, please ensure that it overlaps the black lines if the image is a full bleed. However if it is a PNG, please not that the rest of the box will be transparent. Once the image is placed on the t-shirt, you can then click the Eye logo to preview your product. Next to the Preview button, you can then Download Your Design.