Image Processing Tools

This container has a rich image processing toolkit. Before writing any image code, scan this inventory to pick the best tool for the job — don't default to Pillow for everything.

Tool Selection by Task

Format Conversion & Batch Operations

ImageMagick convert is the default choice. Handles 260+ formats, single command, no code needed.

convert input.png output.webp
convert input.png -quality 85 output.jpg
mogrify -format webp *.png          # batch in-place

For animated formats (GIF↔WebP↔APNG, video↔frames), prefer ffmpeg.

Resize, Crop, Thumbnails

ImageMagick for CLI one-liners. Pillow when already in Python pipeline.

convert input.jpg -resize 800x600 output.jpg          # fit within box
convert input.jpg -resize 800x600^ -gravity center -extent 800x600 output.jpg  # fill+crop
convert input.jpg -thumbnail 200x200^ -gravity center -extent 200x200 thumb.jpg

IM supports 30+ resize filters: -filter Lanczos (sharp downscale), -filter Mitchell (balanced), -filter Point (nearest-neighbor/pixel art).

Compositing & Overlays

ImageMagick composite or convert with -composite. Supports all Porter-Duff modes.

composite -gravity southeast watermark.png photo.jpg output.jpg
convert base.png overlay.png -gravity center -composite result.png

For complex multi-layer work or programmatic positioning, use Pillow (Image.paste, Image.alpha_composite).

Montages, Collages, Contact Sheets

ImageMagick montage — purpose-built for grid layouts.

montage *.jpg -geometry 200x200+5+5 -tile 4x3 sheet.jpg
montage *.png -label '%f' -geometry +4+4 catalog.png

Animated GIFs & Frame Sequences

ImageMagick for simple GIF assembly. ffmpeg for anything involving timing control, video sources, or optimization.

convert -delay 10 -loop 0 frame_*.png animation.gif        # IM
ffmpeg -framerate 10 -i frame_%03d.png -vf palettegen palette.png && \
ffmpeg -framerate 10 -i frame_%03d.png -i palette.png -lavfi paletteuse output.gif  # optimized

imageio is convenient for frame-sequence GIFs from Python arrays.

Image Analysis & Measurement

identify for quick metadata and stats. OpenCV for structural analysis. scikit-image for scientific measurement.

identify -verbose image.png          # full metadata dump
identify -format '%wx%h %[colorspace] %[depth]bit' image.png   # targeted

• OpenCV (cv2): histograms, contour detection, template matching, edge detection, color distribution
• scikit-image (skimage): region properties, morphology, thresholding (Otsu, adaptive), feature detection (SIFT via OpenCV, ORB), SSIM comparison
• scipy.ndimage: convolution, interpolation, labeling connected components

Image Comparison & Diffing

ImageMagick compare produces visual diffs directly.

compare image1.png image2.png diff.png
compare -metric RMSE image1.png image2.png null: 2>&1   # numeric similarity

For structural similarity: skimage.metrics.structural_similarity (SSIM).

Color Operations

ImageMagick handles color space conversion, channel manipulation, color quantization.

convert input.jpg -colorspace Gray output.jpg
convert input.png -colors 16 reduced.png           # quantize
convert input.jpg -modulate 110,130,100 output.jpg  # brightness,saturation,hue
convert input.png -channel R -separate red_channel.png

For programmatic color analysis (dominant colors, palettes): OpenCV k-means on pixel arrays, or Pillow getcolors().

Effects & Filters

ImageMagick has extensive built-in effects:

convert in.png -blur 0x3 out.png              # Gaussian blur
convert in.png -sharpen 0x1 out.png
convert in.png -shadow 60x4+2+2 out.png       # drop shadow
convert in.png -vignette 0x40 out.png
convert in.png -sketch 0x10+120 out.png
convert in.png -charcoal 2 out.png
convert in.png -edge 1 out.png
convert in.png -emboss 1 out.png
convert in.png \( +clone -background black -shadow 60x4+0+0 \) +swap -background none -layers merge +repage rounded.png

For advanced/custom convolution kernels: scipy.ndimage or OpenCV.

Metadata & EXIF

identify -verbose reads all metadata. Pillow reads/writes EXIF programmatically.

identify -verbose image.jpg | grep -A20 'Properties:'

from PIL import Image
img = Image.open("photo.jpg")
exif = img.getexif()  # dict-like access to EXIF tags

Note: no exiftool in this container. Use identify or Pillow for metadata tasks.

Icons, Favicons, App Icons

ImageMagick generates multi-size ICO files directly.

convert icon.png -define icon:auto-resize=256,128,64,48,32,16 favicon.ico

For icon sets (iOS/Android), batch-resize with convert or mogrify to each required size.

PDF & EPS (limited)

ImageMagick can read/write PDF and EPS but Ghostscript is not installed — complex PDF rasterization may fail. For PDF-to-image, prefer Pillow (for simple cases), pdfplumber (text/table extraction), or the pdf skill (for full PDF manipulation). IM's built-in PDF delegate handles basic operations.

Seam Carving (Content-Aware Resize)

ImageMagick has Liquid Rescale (LQR) built in:

convert input.jpg -liquid-rescale 80x100%! output.jpg   # shrink width 20%, preserve content

SVG Handling

ImageMagick rasterizes SVG via its built-in delegate. For SVG→PNG at specific sizes:

convert -density 300 input.svg -resize 800x output.png

No Inkscape or rsvg-convert available. For SVG manipulation, work with the XML directly or use Python's lxml.

Complete Tool Inventory

Tool	Type	Key Strength
ImageMagick 6.9	CLI suite	260 formats, effects, compositing, batch ops
ffmpeg	CLI	Video/animation, frame extraction, optimized GIFs
Graphviz	CLI	Diagram→image rendering (dot, neato, etc.)
LibreOffice	CLI	Document→image conversion
Pillow 12.1	Python	General-purpose, EXIF, drawing, WebP/AVIF, freetype
OpenCV 4.13	Python	Computer vision, histograms, contours, morphology
scikit-image 0.26	Python	Scientific analysis, SSIM, segmentation, features
Wand 0.6	Python	Full ImageMagick API from Python
imageio 2.37	Python	Unified I/O, GIF frame sequences
scipy.ndimage	Python	Convolution, interpolation, labeling
numpy	Python	Raw pixel array math
reportlab	Python	PDF generation with embedded images

Key Constraints

• No Ghostscript — PDF/EPS rasterization is limited to IM's built-in delegate
• No potrace/autotrace — bitmap-to-vector tracing unavailable
• No standalone optimizers — no optipng, pngquant, jpegoptim, gifsicle (use IM quality settings or ffmpeg instead)
• No exiftool — use identify or Pillow for metadata
• No Inkscape — SVG manipulation is XML-level only
• HEIC/AVIF read-only in ImageMagick; Pillow supports AVIF read/write
• ImageMagick is v6 — use convert/identify commands, not magick (v7 syntax)