You can’t rotate a picture once it is uploaded to cakesdecor.com. You have to rotate it before you upload it using a photo editing program. Do you have a editing program? All programs are different on how to rotate them. If you let us know what programs you have I am sure someone can help you out.
If you are on a PC you can use Windows Photo Viewer simply to rotate the pic for you. If you open it in this program and then click rotate buttons at the bottom and then close it will save the photo the way you rotate it.