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id-photo-tool

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Replace an ID photo background color (blue/white/red) and/or add a configurable text watermark when you need compliant ID-photo variants from local JPG/PNG files.

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How to use this skill

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  2. Copy the prompt below and paste it into your agent.
  3. Review the proposed files and risks before you approve installation.
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Source SKILL.md: https://github.com/aipoch/medical-research-skills/blob/HEAD/scientific-skills/Other/id-photo-tool/SKILL.md

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First, summarize what it does, its dependencies, license status if identifiable, and any risks. Show the exact files you propose to add under .agents/skills/id-photo-tool/. Do not write files or run scripts until I approve.

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Source: https://github.com/aipoch/medical-research-skills

When to Use

  • You need to convert an ID photo background to a required solid color (blue/white/red) for official submissions.
  • You need to add a visible “for application only” style watermark to prevent misuse of shared ID photos.
  • You need to batch-generate multiple variants while keeping the original image unchanged (explicit output path).
  • You need an offline, local-only tool (no network access) for processing sensitive personal images.

Key Features

  • Background color replacement for ID photos:
    • Supported target colors: blue, white, red
    • Detects the dominant background color using edge pixels and replaces it using color-distance matching
  • Text watermark overlay:
    • Supported positions: top-left, top-right, bottom-left, bottom-right, center
    • Configurable opacity, font size, and font color
  • Input/output constraints:
    • Supports JPG and PNG only
    • Output keeps the same format as the input
    • Does not overwrite the original file (output path must be provided)
  • Local processing only:
    • Reads only from user-provided input paths and writes only to user-provided output paths

Dependencies

  • Python 3.x
  • pillow (PIL) — version not pinned
  • numpy — version not pinned

Install:

python -m pip install pillow numpy

Example Usage

Background color replacement (JPG):

python scripts/id_photo_tool.py change-bg \
  --input input.jpg \
  --output output.jpg \
  --color blue

Background color replacement (PNG):

python scripts/id_photo_tool.py change-bg \
  --input input.png \
  --output output.png \
  --color white

Add a text watermark:

python scripts/id_photo_tool.py add-watermark \
  --input input.jpg \
  --output watermarked.jpg \
  --text "For application use only"

Implementation Details

Background Color Replacement

  • Background sampling: The tool estimates the original background color by sampling pixels along the image edges (where background is most likely present).
  • Color-distance based replacement: Pixels close to the estimated background color (by color distance) are treated as background and replaced with the selected target color.
  • Supported target colors:
    • blue
    • white
    • red

Text Watermark

  • Placement: One of five positions is supported: top-left, top-right, bottom-left, bottom-right, center.
  • Rendering parameters:
    • Opacity controls watermark transparency.
    • Font size controls text scale.
    • Font color controls text color.
  • Output behavior: The watermark is composited onto the image and saved to the specified output path without modifying the original input file.

Security / Compliance Notes

  • No network access is used; all processing is performed locally.
  • The script only accesses file paths explicitly provided via CLI arguments.
  • The tool requires an explicit output path and does not overwrite the original file by default.