Screenshots & Previews
Organise, render, and upload App Store screenshots and preview videos — per device, per locale.
Screenshots tab
Mainline has a dedicated Screenshots tab, separate from the App Detail view. It uses a project-based model — you organise your screenshot assets into projects, then upload to one or more app versions from a project.
Projects
A project is a collection of screenshot images grouped by device type and locale. You can have multiple projects (e.g. one per app, or one per major version) and reuse them across localizations.
Creating a project
- Tap + in the Screenshots tab to create a new project.
- Give the project a name.
- Add images for each device class and locale you need. Drag images into device slots or use the document picker.
Supported device classes
Mainline handles the screenshot size classes ASC requires:
- iPhone 6.7” (iPhone 15 Pro Max / 14 Plus)
- iPhone 6.5” (iPhone 14 Pro Max and earlier)
- iPhone 5.5” (iPhone 8 Plus era)
- iPad Pro 12.9”
- iPad Pro 11”
Check ASC’s current requirements for which sizes are mandatory for your target devices.
Locale management
Each project can have screenshots in multiple locales. Use Manage Locales within a project to add or remove languages. You can also copy a locale’s screenshot set to another locale within the same project.
Uploading to ASC
When your screenshots are ready:
- Open the project and tap Upload to App Store Connect.
- Choose the target app and version.
- Select which device sizes and locales to upload.
- Tap Upload. Mainline handles the multipart upload to ASC.
You can reorder screenshots within a slot by dragging, and delete individual images with a swipe. Changes are applied to ASC immediately on each action.
Preview videos
Preview video upload is not yet supported in Mainline. Video previews can be managed via App Store Connect in the browser.
Duplicating projects
Tap Duplicate on any project to make a copy. Useful when you’re starting a new version that needs mostly the same screenshots with minor updates.