Inspect assets with clear limits.
Everything you need to use the browser checker and understand what its results mean.
Getting started
Open the browser app, add up to five PNG or JPEG images, confirm the intended asset target, review every result group, and create corrected copies only for changes you approve.
Supported asset types
The catalog includes current common iPhone and iPad screenshot groups, Mac App Store screenshots, In-App Purchase promotional images and review screenshots, and deliberately limited app-icon source checks.
Browser validation
Preflint reads PNG and JPEG signatures, dimensions, alpha capability, transparency metadata, actual decoded transparency, density markers, and basic embedded color-profile indicators. Results are deterministic errors, warnings, manual checks, passes, or information.
Fix behavior
Re-export PNG or JPEG, remove most metadata through browser encoding, flatten onto a chosen color, or resize with padding or crop. Preflint never stretches an image and never modifies the original File.
Privacy
Files, names, metadata, and pixel data are never uploaded. They are held in memory through File, Blob, ArrayBuffer, and temporary object URLs. Clearing removes records and revokes URLs.
Mac app differences
The Mac app adds folders, larger batches, Finder integration, advanced ICC and ColorSync inspection, native shortcuts, more reliable metadata access, and richer reports.
Rule sources
Production rules come only from official Apple documentation. The catalog carries stable IDs, a schema version, a rule version, verification date, browser capability, fix risk, and source URL.
Browser limitations
Canvas exports do not guarantee exact ICC profiles or density metadata. File-system, folder picker, worker canvas, clipboard, and direct-write APIs differ by browser. Mobile memory limits can prevent very large images from decoding.