Image Resize

Resize one image file to a user-specified width and height via ImageMagick. Both dimensions are required — do not run this skill until the user (or task) provides target pixel size.

Rules

When this skill applies, read and follow dependency-manager — run scripts as documented, install missing tools into .dependency/.

• Require target size first. If width/height are missing, ask the user before running.
• Single file only. Pass one image with --image; directories are not supported.
• Run resize.py through the bundled script — do not hand-write magick -resize commands.
• Never overwrite source files. Output goes to image-resize/ (or --output) by default.
• populated: false for imagemagick is not a reason to skip. Install first, set populated: true, retry the same command.

Setup (first run)

1. Download ImageMagick portable build from imagemagick.org and extract to .dependency/imagemagick/.

   Windows result example: .dependency/imagemagick/magick.exe

2. Register in .dependency/manifest.json:

"imagemagick": {
  "populated": true,
  "bin": ".dependency/imagemagick/magick.exe"
}

Use bin/magick on Unix (no .exe).

Quick Start

Both --width and --height are required:

.dependency/python/python .ai/image-resize/resize.py --image assets/sprites/hero.png --width 128 --height 128

Example: assets/ui/icon.png → assets/ui/image-resize/icon.png at 64×64

Custom output path:

.dependency/python/python .ai/image-resize/resize.py --image assets/icons/badge.png -o assets/icons_64 --width 64 --height 64

Resize Modes

# Fit within 128×128 (default — no distortion)
.dependency/python/python .ai/image-resize/resize.py --image assets/hero.png --width 128 --height 128

# Cover 128×128, crop center
.dependency/python/python .ai/image-resize/resize.py --image assets/hero.png --width 128 --height 128 --mode fill

# Stretch to exactly 128×128
.dependency/python/python .ai/image-resize/resize.py --image assets/hero.png --width 128 --height 128 --mode exact

Defaults

Supported inputs: .jpg, .jpeg, .png, .webp, .gif, .bmp, .tif, .tiff, .avif, .ico.

Agent Workflow

1. Confirm size — get explicit width and height from the user (e.g. "128×128", "64 wide and 64 tall"). Do not guess from context unless the user already stated dimensions.
2. Pick mode — default fit; use fill for square thumbnails from non-square art; use exact only when the user accepts distortion.
3. One file per run — resize one image, verify dimensions, then repeat for additional files if needed.
4. Paths — pass whatever image path the user gives; output lands in image-resize/ next to that file by default.
5. Revert — delete output file or git restore; sources are never modified.

Agent Notes

1. Use the bundled script, not hand-written ImageMagick commands.
2. Missing Python/ImageMagick → populate .dependency/ per dependency-manager, retry same command.
3. Do not copy, move, or replace the source with resized output — tell the user where the output file is.
4. Need format conversion only (no resize) → image-to-png.
5. Need trim borders after resize → image-trim.

Troubleshooting

CLI

Copy-paste commands: cli/image-resize.md