You can also overcameovercome this problem with
git mergetool which causes git to create local copies of the conflicted binary and spawn your default editor on them:
{conflicted}.HEAD{conflicted}{conflicted}.REMOTE
Obviously you can't usefully edit binaries files in a text editor. Instead you copy the new {conflicted}.REMOTE file over {conflicted} without closing the editor. Then when you do close the editor git will see that the undecorated working-copy has been changed and your merge conflict is resolved in the usual way.