have pictures stored in a tag / how can i transfer them all at once to a new folder

The tag is simply something a user creates to identify similar files. Open a Finder window and open Finder Preferences ( Command + , ) and ensure the Sidebar is showing (if it isn't look for "Show Sidebar" in View menu) Click the Sidebar tab and ensure the Tags (at the bottom are checked). Next select the tag you want, then select one file and Command + A and then type Command + C, then navigate to where you want to copy to and type Command + V.

What are you calling a tag?

Go up on the menu bar to Edit > Select All, then Copy n Paste or Drag n Drop them all at once to the new folder..

select the tags folder, go up on the menu bar to Edit > Select All, then Copy n Paste or Drag n Drop them all at once to the new folder..