The moth in your photograph is actually a butterfly. It is the small white or cabbage butterfly, Pieris rapae (Lepidoptera: Family: Pieridae). This butterfly is common in Europe, Asia and northern Africa, and has also been accidentally introduced into North America, Australia and New Zealand. Unfortunately, the caterpillars of this butterfly, the "imported cabbageworm", can be pests on plants in the cabbage and mustard family. I have included a link to a website with more information and photos of this insect.