Finder shows your projects' pictures: saved projects now have a thumbnail as their Finder icon, and pressing Space previews them. This adds only a couple of hundred KB per project.
New Canvas has preset sizes in a ⋮ menu beside the title: 4K, 1440p and 1080p; iPhone 18 Pro and Pro Max, MacBook Pro 14" and 16", and Studio Display; and Instagram Square, Portrait and Story, and YouTube Thumb.