Tool library / Writing & media

MaskHarbor Studio · Feature guide · 11 November 2026

Cover private details in an image before sharing it

By İsmail Tekindemir · 3 min read

Ownership disclosure: Taskfield Journal and all 17 featured sites are operated by İsmail Tekindemir. These are owner-written product guides, not independent reviews or paid third-party rankings. No ratings, user counts or traffic claims are implied.

Opaque rectangles, exact coordinates and a fresh flattened PNG review after every edit.

MaskHarbor replaces selected rectangles with solid black pixels in a newly encoded PNG. It is deliberately manual: you decide what needs covering and inspect the whole result. A percentage of masked pixels is geometric coverage, not a claim that all private information has been found.

What it does

• Open one PNG/JPEG/WebP locally: up to 20 MB, 8,000 pixels per edge and 16 million pixels total.
• Draw up to 100 opaque black rectangles, or enter exact whole-pixel X/Y/width/height inside the image.
• Select masks from a coordinate inventory, update/remove them and undo up to 30 saved states.
• On the focused image control, arrow keys move a selected mask by one pixel; Shift plus arrow moves it by ten.
• Use Fit/100%/200% display zoom without changing mask coordinates; a new image resets zoom and masks.
• Masked-pixel coverage counts overlapping rectangles once. Green selection outlines stay on a separate editor layer.
• Build a full-resolution flattened PNG preview, inspect it and tick the review checkbox before download.
• Any mask edit invalidates the old preview and disables download until a fresh result is reviewed. Export a TXT coordinate inventory separately.

A practical workflow

1. Open a static image and inspect every region, including repeated details and thumbnails.
2. Cover private regions and refine edges using coordinates or keyboard movement.
3. Build the PNG preview after the final change and inspect it at useful zoom.
4. Download the -masked.png output, open it for a final check and share that file rather than the original.

A worked use case

In the 1000×600 fictional example, X=50, Y=200, width=520, height=170 covers 88,400 pixels. The exported sample was decoded during QA to check those pixels were opaque black, not merely an editor overlay.

What you can keep

• Flattened PNG
• TXT coordinate inventory; no editable image project

Image and mask data remain in tab memory. No autosave or upload; opening a new image resets the workspace.

What it does not promise

• No automatic face/text detection, privacy certification, PDF, video or animation redaction is performed. SVG/GIF/HEIC are not accepted.
• The new PNG contains no app editing layer or copied source EXIF block, but this is not a forensic metadata certification. Visible content outside masks remains.
• Downloading does not overwrite/delete the original. The TXT inventory cannot restore an image-editing session.

Where to go next

Visit MaskHarbor Studio or compare the other writing & media workflows.