You could create an action which would reduce your workload and save a bit of time
open one of the pictures then go to your Actions panel, if it isnt already open you can open it through Window>Actions. Choose 'New Action' from the sub menu in the Actions panel that you just opened, name your new action when prompted and press ok. The red cirle should appear on this panel, this is the record indicator
Now PS will be recording everything you do so go to Image Size and type in the required dimensions you wish your picture to be, press ok.
go to file>save, press ok, close your picture
now go to the action panel again and press the Square/Stop icon, this stops the recording.
Now open the rest of the pictures you need to resize, when theyre all open, select one and go to your action panel again, highlight the new action youve just created and press the play/run button to the right of record. It should repeat what you did with the last photo.
You still have to do them one at a time but it should be quicker than the other way
hope that helps a bit