Pixieset sell many print sizes and your photos will not fit every print size. When you order a print, your photo will most likely be cropped to fit the specific size. You will have the chance for adjust the crop before placing the order. After you have added the item to card, in the Shopping Cart view, click on Edit Crop to adjust and save the desired crop.
When adding an item into the shopping cart, you will see crop lines if you photo doesn't fit.
If it's a canvas wrap product, they will also see extra crop lines for the "wrap".