In Sweden, a Photo ID is not needed. All that is needed is that you have your voters paper, which is sent to you by post.
Voting fraud in Sweden has typically been cases in which SAP party members have helped typically elderly people to vote, which you are not allowed to do, as you can then influence the voting.
That somebody is voting with somebody else voter paper is quite unusual, and the effects of that seem to be lower than straight miscounting, although it is of course hard to know for sure.
So no, a Photo ID should not be required, it's not necessary.