Google Drive is Google's file sync app that lets you store all of your files online alongside your Google Docs documents, and keep them synced with all of your devices.
Log campaign proof decisions before the next review handoff.
Your proof tasks show who decided, which file version they reviewed, and who takes the next step.
Put the current campaign proof in the reviewer's task.
Your reviewers get a clear task for the current proof. They know what decision to make and when it is due.
Put revised campaign creative back before its reviewer.
Your reviewer gets a task ready to review, with the replacement proof and its version named in a comment.
Route rejected campaign visuals back to their original makers.
Your original maker gets the rework task and sees why the reviewer rejected the proof, with the reason tied to the reviewed file.