We originally created our Frame + Matting Mockup Kits so we could mockup our own images and show our custom framing/matting clients exactly what their framed artwork would look like before they purchased it. So if a client requested a 12" x 18" print with 3"-wide forest green matting and a 1-1/4" silver metal frame, we could mock up their request exactly to their size and color specifications. We found that the most commonly requested artwork size was 12" on the short size (12x12, 12x18, 12x15 [8x10]), the most common matting width was 3" or narrower, and the most commonly requested frame width was 1-1/4" and 3/4". So that is the sizing we used for these templates. You can use the Photoshop software measurement tools with these templates to mockup up larger or smaller artwork to scale too. You accomplish this by changing the matting widths and/or by masking out parts of the frames to create narrower frames as needed. We later created a Matting Expansion Pack so we could create mockups for customers that wanted wider matting - something that isn't easily accomplished with the 3" matting already included in this mockup kit (you can easily go narrower but not wider with the 3" matting included in this mockup kit.) Using the Photoshop software measurement tools and creating layer masks requires slightly more advanced skills. We hope to create an instructional video that shows how to accomplish this, but in the meantime, feel free to reach out to us if you need help.