Imagemagick

ImageMagick — agent safety rules + decision logic

Full recipes: skills/imagemagick/references/recipes.md (compositing, montages, batch, color adjustments). Extended doc: skills/imagemagick/references/FULL_SKILL.md.

This host runs ImageMagick 6: the commands are convert, identify, montage, composite (not the v7 magick prefix).

Safety policy (always)

• Never overwrite the input: write to a new output path unless the user explicitly asks for in-place.
• Quote every path. Local files only — never pass user-supplied URLs.
• Verify output after processing: identify -format "%f %wx%h %m %b\n" "$OUTPUT"
• -limit memory 256MiB -limit disk 512MiB on large batch runs.
• PDF/PS/EPS coders may be policy-restricted; on a policy error, don't bypass — use the document.* pdf tools instead.

Inspect first

identify -format "%f  %wx%h  %m  %[colorspace]  %b\n" "$INPUT"

Core moves

# Resize to width 800 (aspect kept, never upscale):
convert "$INPUT" -resize '800x>' "$OUTPUT"

# Crop 400x300 starting at (50,20):
convert "$INPUT" -crop 400x300+50+20 +repage "$OUTPUT"

# Convert format (quality for jpg):
convert "$INPUT" -quality 90 "$OUTPUT.jpg"

# Horizontal strip / side-by-side (use -append for vertical):
convert a.png b.png c.png +append "$OUTPUT"

# Grid montage, 3 across, small gaps:
montage *.png -tile 3x -geometry +4+4 "$OUTPUT"

# Text watermark bottom-right:
convert "$INPUT" -gravity southeast -pointsize 24 -fill 'rgba(255,255,255,0.6)' \
  -annotate +12+12 'watermark' "$OUTPUT"

# Overlay logo at top-left with offset:
composite -gravity northwest -geometry +10+10 logo.png "$INPUT" "$OUTPUT"

# Batch convert (mogrify writes to -path, inputs untouched):
mkdir -p out && mogrify -path out -format jpg -quality 88 *.png

Common failure modes

• Cropped image keeps old canvas offset → add +repage after -crop.
• Blurry upscales → use > in resize geometry so images only shrink.
• Transparent PNG → JPG gets black background → add -background white -flatten before writing.
• Odd colors after ops → check colorspace (-colorspace sRGB).

Agent behavior

• State the transformation in one line before running it.
• Chain operations in ONE convert call rather than multiple lossy passes.
• sudo-ai also has media.image-edit-advanced (resize/crop/rotate/watermark via sharp) — prefer it for single-image basics; use ImageMagick for montages, strips, batches, and anything sharp doesn't cover. For color/ accessibility checks use media.color-audit.