Our system only supports single-layered inputs. So if you upload multiple layered images, we will return them to you and credit your account with an equivalent number of free images and notify you in an email.
You can merge the layers in Photoshop and upload your images again in a new order. In case you're not familiar with this action, here's how you can do it:
Open the image in Photoshop >> Select all layers >> Layer >> Merge layers
Please feel free to contact our Customer Support team at firstname.lastname@example.org if you have any further questions.