Scanned documents or photocopies may be acceptable in business transaction. It depends upon the document and the business. This means that in the normal course of business they may be accepted as genuine without question.
However, any such copied documents presented to a court are only acceptable if they are "certified" copies as has been mentioned. Either side in the case has the right to challenge their authenticity and, if necessary, require evidence to be given by the person who made the copy.