| name | image-forge |
| description | Edit images with precision using ImageMagick 7, sips, transparent-background, and Pillow — with intelligent routing to AI semantic editing (Gemini/nano-banana-pro) for content-aware operations. Covers cropping, resizing, compositing, annotating, format conversion, color adjustment, background removal, batch processing, and montage creation. Triggers on image editing, crop, resize, composite, annotate, remove background, format conversion. |
Image Forge
Pixel-precise image editing with three-tier routing: deterministic CLI tools for exact operations, AI models for semantic edits, vision models for analysis.
Routing Decision
Use AI when the edit requires understanding what is in the image. Use ImageMagick when the edit requires knowing exactly what to do to the pixels.
Tier 1: Deterministic (magick, sips, transparent-background)
Use for operations with exact, numeric parameters:
| Task | Tool | Command |
|---|
| Resize to exact dimensions | magick | magick in.jpg -resize 800x600! out.jpg |
| Resize fit (preserve aspect) | magick | magick in.jpg -resize 800x600 out.jpg |
| Resize fill + crop | magick | magick in.jpg -resize 800x600^ -gravity center -extent 800x600 out.jpg |
| Resize shrink only | magick | magick in.jpg -resize '800x600>' out.jpg |
| Crop at offset | magick | magick in.jpg -crop 600x400+100+50 +repage out.jpg |
| Center crop | magick | magick in.jpg -gravity center -crop 600x400+0+0 +repage out.jpg |
| Auto-trim whitespace | magick | magick in.jpg -fuzz 10% -trim +repage out.jpg |
| Format convert | magick | magick in.png -quality 85 out.jpg |
| Add text | magick | magick in.jpg -fill white -pointsize 36 -annotate +10+50 'Text' out.jpg |
| Composite overlay | magick | magick bg.png fg.png -geometry +50+100 -composite out.png |
| Watermark | magick | magick photo.jpg wm.png -gravity SouthEast -geometry +10+10 -compose Dissolve -define compose:args=25 -composite out.jpg |
| Adjust brightness/contrast | magick | magick in.jpg -brightness-contrast 10x20 out.jpg |
| Adjust saturation | magick | magick in.jpg -modulate 100,130,100 out.jpg |
| Grayscale | magick | magick in.jpg -colorspace Gray out.jpg |
| Sepia | magick | magick in.jpg -sepia-tone 80% out.jpg |
| Blur | magick | magick in.jpg -blur 0x3 out.jpg |
| Sharpen | magick | magick in.jpg -sharpen 0x1 out.jpg |
| Remove background (AI) | transparent-background | See Background Removal section below |
| Remove background (simple) | magick | magick in.jpg -fuzz 15% -transparent white -trim +repage out.png |
| Strip metadata | magick | magick in.jpg -strip out.jpg |
| Set DPI | magick | magick in.jpg -density 300 out.jpg |
| Batch resize | batch_ops.py | python3 scripts/batch_ops.py *.jpg --op resize --width 800 --output resized/ |
| Montage/contact sheet | magick | magick montage *.jpg -geometry 200x200+5+5 -tile 4x out.jpg |
| Quick format convert (macOS) | sips | sips -s format jpeg in.png --out out.jpg |
| Quick resize (macOS) | sips | sips -Z 800 in.jpg --out out.jpg |
Tier 2: AI Semantic (nano-banana-pro / Gemini)
Delegate to the nano-banana-pro skill when the edit requires understanding image content:
- Remove a person/object from a photo
- Change sky, weather, time of day
- Apply artistic style transfer
- Inpaint/outpaint regions
- Generate new image from scratch
- Content-aware fill after object removal
Nano Banana regenerates, it does not edit. Every call re-rolls the entire frame, even when the prompt asks to preserve regions verbatim. Expect ~40% of pixels to drift outside the target area — measured empirically, not hypothesized. For surgical regional edits (change the face, keep everything else identical), use the hybrid pattern in references/compositing.md § Surgical Regional Edits: let NB produce a drifted reference, then composite only the target region onto the pristine original with a feathered alpha mask.
Nano Banana also supports only discrete aspect ratios (1:1, 2:3, 3:2, 3:4, 4:3, 4:5, 5:4, 9:16, 16:9, 21:9). For inputs at other ratios (e.g. 3:1 panoramics), see references/recipes.md § Aspect Ratio Padding for the pad-generate-crop recipe.
Tier 3: Vision Analysis (Claude Read tool)
Use the Read tool to inspect images before/after edits:
- Verify an edit succeeded
- Describe image contents
- Check composition and framing
- Identify colors, objects, text in image
Background Removal
Use transparent-background (InSPyReNet model) for AI background removal. It produces clean alpha mattes with smooth anti-aliased edges — far superior to ImageMagick's -transparent/-fuzz approach, which leaves white fringing in concave regions and jagged edges.
When to use each:
| Method | When | Quality |
|---|
transparent-background | Any photo/render with complex foreground (hair, translucent edges, concave regions) | Smooth alpha, no fringing |
magick -transparent white -fuzz N% | Simple shapes on pure white, quick-and-dirty | Fast but aliased edges, misses interior white |
magick floodfill | Remove background from corners only, preserve interior white | Only hits connected regions |
Python API (recommended):
from transparent_background import Remover
from PIL import Image
remover = Remover()
img = Image.open("input.jpg").convert("RGB")
out = remover.process(img, type="rgba")
out.save("output.png")
With trim (most common workflow):
python3 -c "
from transparent_background import Remover
from PIL import Image
remover = Remover()
img = Image.open('input.jpg').convert('RGB')
remover.process(img, type='rgba').save('/tmp/nobg.png')
"
magick /tmp/nobg.png -trim +repage output.png
Install: uv pip install --system transparent-background
Performance: ~2-3s per image on Apple Silicon (MPS). First run downloads the InSPyReNet model (~170MB).
Note: rembg is an alternative but has a broken gradio dependency as of May 2026. transparent-background is the more reliable option.
Scripts
All scripts are in ~/.claude/skills/image-forge/scripts/. Run with python3.
image_info.py — Inspect Image Metadata
python3 ~/.claude/skills/image-forge/scripts/image_info.py photo.jpg
python3 ~/.claude/skills/image-forge/scripts/image_info.py photo.jpg --field dimensions
python3 ~/.claude/skills/image-forge/scripts/image_info.py photo.jpg --field width
Returns clean JSON: dimensions, format, color space, depth, alpha, DPI, ICC profile, EXIF.
image_pipeline.py — Declarative Edit Pipeline
Write a JSON spec, get a single chained magick command. No intermediate files.
cat > /tmp/pipeline.json << 'EOF'
{
"input": "photo.jpg",
"output": "result.png",
"steps": [
{"op": "resize", "width": 800, "height": 600, "mode": "fill"},
{"op": "brightness_contrast", "brightness": 5, "contrast": 10},
{"op": "annotate", "text": "Title", "gravity": "South", "pointsize": 36, "fill": "white", "stroke": "black", "strokewidth": 2},
{"op": "composite", "overlay": "watermark.png", "gravity": "SouthEast", "opacity": 25},
{"op": "quality", "value": 90},
{"op": "strip"}
]
}
EOF
python3 ~/.claude/skills/image-forge/scripts/image_pipeline.py /tmp/pipeline.json --dry-run
python3 ~/.claude/skills/image-forge/scripts/image_pipeline.py /tmp/pipeline.json
Available operations:
| Op | Parameters |
|---|
resize | width, height, mode (fit/fill/exact/shrink/enlarge/percent), filter |
crop | w/width, h/height, x, y, gravity |
trim | fuzz (%) |
annotate | text, font, pointsize, fill, stroke, strokewidth, gravity, x, y |
composite | overlay, gravity, x, y, opacity, compose, resize |
rotate | angle, background |
blur | sigma, radius |
sharpen | sigma, radius |
unsharp | sigma, radius, amount, threshold |
modulate | brightness, saturation, hue (100 = no change) |
brightness_contrast | brightness, contrast |
levels | black, white, gamma |
gamma | value |
sigmoidal_contrast | strength, midpoint |
colorize | color, amount (%) |
sepia | threshold (%) |
grayscale | (none) |
negate | (none) |
auto_level | (none) |
normalize | (none) |
auto_orient | (none) |
flip / flop | (none) |
border | color, size |
extent | width, height, background, gravity |
shadow | opacity, sigma, x, y |
transparent | color, fuzz (%) |
alpha_remove | background |
alpha_set | (none) |
quality | value (1-100) |
strip | (none) |
density | value (DPI) |
draw | primitive, fill, stroke, strokewidth |
raw | args (string or array of raw magick args) |
smart_crop.py — Gravity-Based Smart Crop
python3 ~/.claude/skills/image-forge/scripts/smart_crop.py photo.jpg --target 800x600
python3 ~/.claude/skills/image-forge/scripts/smart_crop.py photo.jpg --target 800x600 --gravity north
python3 ~/.claude/skills/image-forge/scripts/smart_crop.py photo.jpg --target 1080x1080 --output cropped/
python3 ~/.claude/skills/image-forge/scripts/smart_crop.py photo.jpg --target 800x600 --dry-run
Gravities: center, north, south, east, west, northwest, northeast, southwest, southeast.
batch_ops.py — Parallel Batch Processing
python3 ~/.claude/skills/image-forge/scripts/batch_ops.py *.jpg --op resize --width 800 --output resized/
python3 ~/.claude/skills/image-forge/scripts/batch_ops.py *.png --op format --to jpg --quality 85 --output converted/
python3 ~/.claude/skills/image-forge/scripts/batch_ops.py *.jpg --op thumbnail --width 200 --height 200 --output thumbs/
python3 ~/.claude/skills/image-forge/scripts/batch_ops.py *.jpg --op strip --output clean/
python3 ~/.claude/skills/image-forge/scripts/batch_ops.py *.jpg --op watermark --overlay wm.png --opacity 25 --output marked/
python3 ~/.claude/skills/image-forge/scripts/batch_ops.py *.jpg --op resize --width 800 --parallel 8 --output resized/
Operations: resize, thumbnail, format, strip, auto_orient, watermark, crop.
montage_builder.py — Contact Sheets
python3 ~/.claude/skills/image-forge/scripts/montage_builder.py *.jpg --output contact.jpg
python3 ~/.claude/skills/image-forge/scripts/montage_builder.py *.jpg --cols 3 --thumb 300x300 --label --output grid.jpg
python3 ~/.claude/skills/image-forge/scripts/montage_builder.py *.jpg --background '#1a1a2e' --border 2 --output dark_grid.jpg
Quick Recipes
Social Media Crops
magick in.jpg -resize 1080x1080^ -gravity center -extent 1080x1080 instagram.jpg
magick in.jpg -resize 1080x1920^ -gravity center -extent 1080x1920 story.jpg
magick in.jpg -resize 1500x500^ -gravity center -extent 1500x500 header.jpg
magick in.jpg -resize 1200x630^ -gravity center -extent 1200x630 og.jpg
Watermark
magick photo.jpg -fill 'rgba(255,255,255,0.3)' -gravity SouthEast \
-font Helvetica -pointsize 24 -annotate +10+10 '© 2026' out.jpg
magick photo.jpg wm.png -gravity SouthEast -geometry +10+10 \
-compose Dissolve -define compose:args=25 -composite out.jpg
Borders and Shadows
magick in.jpg -bordercolor '#333' -border 10 out.jpg
magick in.png \( +clone -background black -shadow 60x5+5+5 \) \
+swap -background none -layers merge +repage shadow.png
Color Effects
magick in.jpg -modulate 105,80,100 -fill '#704214' -colorize 15% \
-sigmoidal-contrast 3x60% vintage.jpg
magick in.jpg -colorspace Gray -sigmoidal-contrast 10x50% bw.jpg
Geometry Syntax Quick Reference
| Syntax | Meaning |
|---|
800x600 | Fit within box, preserve aspect |
800x600! | Force exact (distort) |
800x600> | Shrink only if larger |
800x600< | Enlarge only if smaller |
800x600^ | Fill box (minimum dimension matches) |
50% | Scale by percentage |
+X+Y | Offset from gravity anchor |
Shell escaping: Quote geometry with >, <, ^:
magick in.jpg -resize '800x600>' out.jpg
Critical Reminders
- Always
+repage after -crop — Virtual canvas offset persists without it
-modulate order is B,S,H — Brightness, Saturation, Hue (not H,S,L)- Settings persist, operators execute immediately — Order matters in magick commands
- Use
rembg for background removal — rembg i input.jpg output.png (add -a for alpha matting)
- Quote geometry —
>, <, ^ are shell metacharacters
-alpha off is permanent in IM7 — Use -alpha deactivate/-alpha activate for temporary toggle- Inspect before editing — Run
image_info.py first to know dimensions, format, alpha state
- Pipeline for multi-step — Use
image_pipeline.py instead of chaining shell commands
- Nano Banana drifts the whole frame — Never trust NB to leave regions unchanged. For regional edits, use the surgical composite pattern (see
compositing.md § Surgical Regional Edits). Verify with magick compare -metric AE -fuzz 5% before after diff.png — low AE means clean, ~40%+ means full regeneration.
References
Detailed references in ~/.claude/skills/image-forge/references/:
magick-reference.md — Complete ImageMagick 7 command reference (resize, crop, color, text, drawing, batch, identify)compositing.md — All compositing operators (Duff-Porter, mathematical, lighting, HSL, special)recipes.md — 30+ recipes (borders, shadows, watermarks, social sizing, color effects, sprites, batch patterns)
Dependencies
| Tool | Version | Install |
|---|
| ImageMagick | 7.1.2-7 (Q16-HDRI) | brew install imagemagick |
| rembg | 2.0.72 | uv pip install rembg |
| sips | macOS built-in | — |
| Pillow | 10.4.0 | uv pip install Pillow |
