Getting started
Import two images from Photos or Files and try the size presets. On an ordinary phone compare them vertically and tap to swap order. Record readability, ratings, notes and any manually entered result. Delete comparisons from the project list. Original images, exported copies and device backups are managed separately.
Contact
kkksss.support@icloud.com
Include ThumbnailDuel in the subject, along with the app and iOS versions, device model, steps that led to the issue and any error shown. Tell us whether you used folding input or the on-screen alternative. Do not send passwords or payment details.