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.
Your maker sees linked PDF marks and the next proof deadline in chat. Your approval task keeps the same fixes.
Your review tasks show the current image revision and reviewer due date, so the next handoff is clear.
Your maker gets the fixes in the review task, tied to the PDF version your reviewer marked up.