When this strategy is enabled you will be able to attach images and documents to Tasks and Projects. To enable it, go to ☰ → Strategies and after you turn it on you'll be prompted to add the Attach action to your right-click menu and/or hover buttons. Using this action will let you drag and drop files from your computer to Tasks and Projects, which you can then access from all your devices.
After you attach a file to a task or a project it will be displayed on its right side.
You can store up to 10GB of attachments and in the strategy's settings you can view all your attachments and delete attachments you no longer need.
You can also sort your attachments by clicking on the "Sort" button above your attachments. By default, they're sorted by biggest first.
Emailing attachments to Marvin
If you use the Email to Marvin strategy, then email attachments will be created as Task attachments. You can disable this in the "Email to Marvin" strategy settings.