SIGNA is a local-first watermark and image analysis app.

Use SIGNA to add visible watermarks, add invisible watermarks to your own images, and review selected images directly on your device. SIGNA is designed for users who want more than a simple visible watermark, while keeping image analysis practical, understandable, and privacy-conscious.

Main features:
SIGNA lets you add visible text or logo watermarks to images, add invisible watermarks to your own images, add a SIGNA identification signal together with visible watermarks, check whether an invisible watermark can be read from a selected image, view certification-key reference information when available, review image metadata and processing indicators, review available image-state information including recompression or editing-related traces, and save processed images to your device gallery.

Local-first image analysis:
SIGNA’s core analysis runs on your device. Images are not uploaded to SIGNA servers for analysis. Photo and media access is used only to select images, add watermarks, analyze selected images, and save processed images.

Recommended use:
For the best results, keep original or original-quality image files whenever possible. When sharing images, use original-quality transfer, file transfer, cloud storage, or USB transfer whenever possible.

Messaging apps and social platforms may recompress images, which can damage or remove invisible watermark information.

Known limitations:
Invisible watermarks may be damaged or become unreadable after normal-quality or low-quality transfer, screenshots, strong resizing, recompression, or heavy editing.

If no readable invisible watermark is detected, SIGNA can still review available image-state information, but watermark-based interpretation may be limited.

Important scope:
SIGNA is an image reference and analysis tool. It is not intended to determine legal rights, copyright ownership, identity, original-file status, AI-generation status, or image manipulation with certainty.