What you need
Choose one authorised JPEG, PNG, or WebP still image up to 20 MB and 12 million decoded pixels. Animated frames are not processed.
Image Tools / Local studio
Measure nonzero-alpha pixel density inside the tight axis-aligned visible bounding rectangle.
Step 1 / Source
Or browse for a JPEG, PNG, or WebP image that you own or are authorised to edit.
One file · up to 20 MB · maximum 50 megapixelsStep 2 / Output
This analysis uses one documented method so repeated runs on the same decoded pixels remain comparable.
The selected image is decoded and re-encoded inside this browser tab.
After download, the preview URL, decoded bitmap, canvas, and selected source reference are cleared.
Nirmion cannot remove the finished file from your device or browser download history.
Workflow guide
Choose one authorised JPEG, PNG, or WebP still image up to 20 MB and 12 million decoded pixels. Animated frames are not processed.
Compare transparent symbols for holes or sparse occupancy inside their own visible bounds without conflating padding outside those bounds.
Review and download a separate visible-bounds-fill JSON report; the original file on your device remains unchanged.
Decision guide
The minimum and maximum coordinates with alpha above zero define one inclusive rectangle; visible count divided by rectangle area gives fill percentage.
Bounds fill is not solidity, connectedness, subject segmentation, shape similarity, optical balance, packing efficiency, or artwork approval. Browser-local processing avoids a Nirmion file upload, but it cannot remove copies stored elsewhere.
MDN Canvas pixel manipulationGood to know
Questions answered
No. Supported JPEG, PNG, and WebP decoding, pixel inspection, transformation, and export run in your current browser tab. Nirmion does not send the selected image to its API for this workflow. The result is a separate derivative or JSON report, while the original file on your device remains unchanged and should be retained for comparison.
The minimum and maximum coordinates with alpha above zero define one inclusive rectangle; visible count divided by rectangle area gives fill percentage. Any alpha above zero is visible; a fully transparent image returns null bounds, zero bounded area, and zero fill rather than NaN. The method does not infer subjects, restore missing detail, calibrate a display, or develop raw camera data. Compare edges, gradients, text, texture, and transparent areas with the original before relying on the result.
Bounds fill is not solidity, connectedness, subject segmentation, shape similarity, optical balance, packing efficiency, or artwork approval. The workspace accepts one supported still image up to 20 MB and caps this pixel-intensive operation at 12 million decoded pixels for predictable browser memory use. Results depend on browser decoding and encoding support. Animation, raw development, ICC calibration, layer editing, and batch processing are outside this tool's verified scope.