Resize

Resize images to specified dimensions with advanced options for fit modes, quality control, and various resampling kernels.

Installation

Usage

Basic Usage

Options

Fit Modes

Cover (Default)

Crop to fill dimensions, maintaining aspect ratio:

• Image fills entire area
• Crops overflow
• No distortion
• Use: Thumbnails, profile pictures, social media

Contain

Fit within dimensions, add padding if needed:

• Entire image visible
• May add padding
• No cropping
• Use: Logos, product images, preserve full content

Fill

Stretch to exact dimensions, ignore aspect ratio:

mediaproc image resize image.jpg -w 500 -h 500 --fit fill

• Exact dimensions
• May distort
• No cropping or padding
• Use: When exact size required regardless of distortion

Inside

Resize to fit inside dimensions, smaller or equal:

mediaproc image resize photo.jpg -w 1000 -h 1000 --fit inside

• Fits within bounds
• No enlargement
• Maintains aspect ratio
• Use: Maximum size constraints

Outside

Resize to fit outside dimensions, larger or equal:

mediaproc image resize photo.jpg -w 500 -h 500 --fit outside --background white

• Covers entire area
• May exceed dimensions
• Maintains aspect ratio
• Use: Ensure minimum size coverage

Resampling Kernels

Lanczos3 (Default)

Best quality, slower:

mediaproc image resize photo.jpg -w 800 --kernel lanczos3

• Highest quality
• Sharp results
• Slightly slower
• Best for: Final production, print, detail preservation

Lanczos2

Good quality, faster than lanczos3:

mediaproc image resize photo.jpg -w 800 --kernel lanczos2

• Very good quality
• Faster than lanczos3
• Balanced choice
• Best for: Web images, general use

Mitchell

Smooth results, good quality:

mediaproc image resize photo.jpg -w 800 --kernel mitchell

• Smooth appearance
• Less sharpening than lanczos
• Good quality
• Best for: Photos, portraits, smooth gradients

Cubic

Balanced, moderate quality:

mediaproc image resize photo.jpg -w 800 --kernel cubic

• Standard cubic interpolation
• Moderate quality
• Fast
• Best for: General purpose, batch processing

Nearest

Fastest, lowest quality:

mediaproc image resize pixel-art.png -w 400 --kernel nearest

• No interpolation
• Blocky/pixelated
• Very fast
• Best for: Pixel art, intentional pixelation, speed priority

Position Options

Control where image is positioned for cover and contain modes:

• center (default): Center alignment
• top: Top alignment
• bottom: Bottom alignment
• left: Left alignment
• right: Right alignment
• top left, top right, bottom left, bottom right: Corner alignment

# Align to top when cropping
mediaproc image resize portrait.jpg -w 500 -h 500 --fit cover --position top

# Align to right
mediaproc image resize landscape.jpg -w 800 -h 600 --fit cover --position right

Examples

1. Resize Width Only

Auto-calculate height:

mediaproc image resize photo.jpg -w 800

Result: 800px wide, height maintains aspect ratio.

2. Resize Height Only

Auto-calculate width:

mediaproc image resize portrait.jpg -h 1200

Result: 1200px tall, width maintains aspect ratio.

3. Full HD Resize

Resize to 1920×1080:

mediaproc image resize video-thumbnail.jpg -w 1920 -h 1080

Standard: Full HD dimensions with cover mode.

4. Square Thumbnail

Create square thumbnail:

mediaproc image resize photo.jpg -w 300 -h 300 --fit cover

Social Media: Perfect square for avatars, Instagram.

5. Logo Resize (Preserve Full Image)

Fit logo in box with padding:

mediaproc image resize logo.png -w 200 -h 200 --fit contain --background transparent

Branding: Entire logo visible, no cropping.

6. High-Quality Resize

Maximum quality settings:

mediaproc image resize photo.jpg -w 2000 -q 95 --kernel lanczos3

Print/Production: Best quality for final output.

7. Fast Batch Resize

Quick processing for many images:

mediaproc image resize "photos/*.jpg" -w 1024 --kernel cubic

Speed: Faster kernel for bulk processing.

8. Email-Optimized Size

Resize for email attachments:

mediaproc image resize large-photo.jpg -w 800 -q 80

Email: Smaller file size, reasonable quality.

9. Mobile-Optimized

Resize for mobile display:

mediaproc image resize hero-image.jpg -w 1080 -q 85

Mobile Web: Mobile screen width, good quality.

10. Contain with White Background

Product image with white padding:

mediaproc image resize product.jpg -w 800 -h 800 --fit contain --background white

E-commerce: Product centered on white background.

11. No Aspect Ratio Constraint

Stretch to exact size:

mediaproc image resize image.jpg -w 400 -h 600 --no-maintain-aspect-ratio

Exact: Forces exact dimensions, may distort.

12. Maximum Width Constraint

Don't exceed width:

mediaproc image resize huge-image.jpg -w 2000 --fit inside

Constraint: Won't enlarge beyond 2000px wide.

13. Multiple Outputs

Create different sizes:

# Thumbnail
mediaproc image resize photo.jpg -w 300 -h 300 -o thumb.jpg

# Medium
mediaproc image resize photo.jpg -w 800 -o medium.jpg

# Large
mediaproc image resize photo.jpg -w 1920 -o large.jpg

Responsive: Multiple sizes for responsive web design.

14. Pixel Art Resize

Resize pixel art without smoothing:

mediaproc image resize sprite.png -w 256 -h 256 --kernel nearest

Gaming: Preserves pixel art sharpness.

15. Verbose Output

Show detailed processing info:

mediaproc image resize photo.jpg -w 1000 -v

Info: Original size, new size, processing details.

16. Portrait Crop (Top Alignment)

Crop portrait from top:

mediaproc image resize portrait.jpg -w 400 -h 600 --fit cover --position top

Photography: Keep face/head in frame when cropping.

17. Preview Before Resizing

Dry run to check settings:

mediaproc image resize photo.jpg -w 800 -h 600 --dry-run

Safety: Verify before processing.

Use Cases

1. Web Optimization

Resize for web display:

# Hero image
mediaproc image resize hero.jpg -w 1920 -q 85

# Content images
mediaproc image resize "content/*.jpg" -w 1200 -q 80

# Thumbnails
mediaproc image resize "gallery/*.jpg" -w 400 -h 400 --fit cover

Performance: Faster page loads.

2. Social Media

Standard social media sizes:

# Instagram square
mediaproc image resize photo.jpg -w 1080 -h 1080 --fit cover

# Facebook cover
mediaproc image resize cover.jpg -w 820 -h 312 --fit cover

# Twitter header
mediaproc image resize header.jpg -w 1500 -h 500 --fit cover

Social: Platform-optimized dimensions.

3. E-commerce

Product image standardization:

# Product thumbnails
mediaproc image resize "products/*.jpg" -w 300 -h 300 --fit contain --background white

# Large product images
mediaproc image resize "products/*.jpg" -w 1200 -h 1200 --fit contain --background white

Retail: Consistent product presentation.

4. Email Campaigns

Email-friendly sizes:

# Header images
mediaproc image resize email-header.jpg -w 600 -q 75

# Content images
mediaproc image resize "email-content/*.jpg" -w 500 -q 70

Email: Fast loading, small file sizes.

5. Mobile App Assets

App-specific sizes:

# iOS retina
mediaproc image resize icon.png -w 512 -h 512 --fit contain

# Android icons
mediaproc image resize icon.png -w 192 -h 192 --fit contain

Apps: Platform-specific asset generation.

6. Print Preparation

High-quality for print:

# 300 DPI for 8×10 inch print (2400×3000px)
mediaproc image resize photo.jpg -w 2400 -h 3000 -q 95 --kernel lanczos3

Print: Professional print quality.

7. Blog/CMS

Blog image standards:

# Featured images
mediaproc image resize "blog/*.jpg" -w 1200 -h 630 --fit cover

# Inline images
mediaproc image resize "inline/*.jpg" -w 800

Publishing: CMS-optimized images.

8. Responsive Images

Multiple sizes for srcset:

# Small
mediaproc image resize image.jpg -w 640 -o image-sm.jpg

# Medium
mediaproc image resize image.jpg -w 1024 -o image-md.jpg

# Large
mediaproc image resize image.jpg -w 1920 -o image-lg.jpg

Responsive: Serve appropriate size per device.

9. Avatar/Profile Pictures

User profile images:

# Small avatar
mediaproc image resize avatar.jpg -w 50 -h 50 --fit cover -o avatar-sm.jpg

# Medium avatar
mediaproc image resize avatar.jpg -w 150 -h 150 --fit cover -o avatar-md.jpg

# Large avatar
mediaproc image resize avatar.jpg -w 300 -h 300 --fit cover -o avatar-lg.jpg

Users: Consistent profile picture sizes.

10. Cloud Storage Optimization

Reduce storage usage:

# Resize large photos to reasonable size
mediaproc image resize "uploads/*.jpg" -w 1920 --fit inside -q 85

Storage: Save space, maintain quality.

Combining with Other Commands

Resize + Optimize

Resize and compress:

# Resize
mediaproc image resize huge.jpg -w 1920 -o resized.jpg

# Optimize
mediaproc image optimize resized.jpg --aggressive

Efficiency: Smaller files for web.

Crop + Resize

Crop area, then resize:

# Crop specific area
mediaproc image crop photo.jpg --x 100 --y 100 --width 800 --height 600 -o cropped.jpg

# Resize cropped area
mediaproc image resize cropped.jpg -w 400 -h 300

Precision: Exact area at specific size.

Auto-Enhance + Resize

Enhance then resize:

# Enhance quality
mediaproc image auto-enhance photo.jpg -o enhanced.jpg

# Resize enhanced
mediaproc image resize enhanced.jpg -w 1200

Quality: Better looking resized images.

Resize + Watermark

Resize then add watermark:

# Resize
mediaproc image resize photo.jpg -w 1920 -o resized.jpg

# Add watermark
mediaproc image watermark resized.jpg --text "© 2024" --position bottom-right

Protection: Watermarked web-ready images.

Technical Details

Resampling Algorithms

Lanczos: Windowed sinc function

• lanczos3: 3-lobe window (default)
• lanczos2: 2-lobe window

Mitchell: Mitchell-Netravali filter

• Balanced sharpness and smoothness

Cubic: Cubic convolution

• Standard bicubic interpolation

Nearest: No interpolation

• Pixel replication only

Performance

Approximate times (per megapixel):

• nearest: ~20-40ms
• cubic: ~50-80ms
• mitchell: ~60-90ms
• lanczos2: ~80-120ms
• lanczos3: ~100-150ms

Quality vs Speed

Best Quality: lanczos3 (slowest) Balanced: mitchell or lanczos2 Fastest: nearest (lowest quality)

File Size Impact

Smaller dimensions = smaller file size:

• 50% dimension reduction ≈ 75% file size reduction
• 25% dimension reduction ≈ 44% file size reduction

Example:

• 4000×3000 (12MP) @ 5MB
• 2000×1500 (3MP) @ 1.25MB (75% reduction)

Best Practices

1. Specify At Least One Dimension

Width or height required:

# Must specify at least one
mediaproc image resize photo.jpg -w 800

2. Use Appropriate Fit Mode

Cover: When cropping is acceptable Contain: When full image must be visible Inside: When maximum size matters

3. Choose Correct Kernel

Final output: lanczos3 Web/general: lanczos2 or mitchell Batch/speed: cubic Pixel art: nearest

4. Quality Settings

• 95-100: Print, professional
• 85-90: Web (high quality)
• 75-85: Web (standard)
• 65-75: Email, mobile

5. Maintain Aspect Ratio

Usually want to preserve aspect ratio:

# Good: auto height
mediaproc image resize photo.jpg -w 800

# Usually avoid distortion
# mediaproc image resize photo.jpg -w 800 -h 800 --fit fill

6. Use Dry Run

Test before batch processing:

mediaproc image resize "photos/*.jpg" -w 1024 --dry-run

7. Background Color for Contain

Match background to use case:

# Transparent for web
--background transparent

# White for product images
--background white

# Custom color
--background "#f0f0f0"

Troubleshooting

Issue: Image Distorted

Problem: Image stretched or squashed

Cause: Using fill mode or --no-maintain-aspect-ratio

Solution: Use cover or contain mode

# Distorted
mediaproc image resize photo.jpg -w 500 -h 500 --fit fill

# Better
mediaproc image resize photo.jpg -w 500 -h 500 --fit cover

Issue: Image Cropped

Problem: Parts of image missing

Cause: Cover mode crops to fit

Solution: Use contain mode

# Crops image
mediaproc image resize photo.jpg -w 500 -h 500 --fit cover

# Shows full image
mediaproc image resize photo.jpg -w 500 -h 500 --fit contain

Issue: Padding/Borders

Problem: White/black borders around image

Cause: Contain mode adds padding

Solution: Change background or use cover mode

# Transparent background
mediaproc image resize logo.png -w 200 -h 200 --fit contain --background transparent

Issue: Image Blurry

Problem: Resized image looks soft/blurry

Cause: Using cubic or mitchell kernel, or over-enlargement

Solution: Use lanczos3, avoid extreme enlargement

# Sharper results
mediaproc image resize photo.jpg -w 2000 --kernel lanczos3

Issue: Slow Processing

Problem: Resizing takes too long

Cause: Using lanczos3 on many/large images

Solution: Use faster kernel

# Faster
mediaproc image resize "photos/*.jpg" -w 1024 --kernel cubic

Issue: No Dimension Specified

Problem: Error about missing dimension

Cause: Must specify width or height

Solution: Add -w or -h

# Error
mediaproc image resize photo.jpg

# Fixed
mediaproc image resize photo.jpg -w 800

Related Commands

• crop - Crop specific area before resizing
• thumbnail - Quick thumbnail generation
• optimize - Further optimize file size
• smart-crop - Content-aware cropping

Further Reading

• Image Scaling
• Lanczos Resampling
• Mitchell-Netravali Filters
• Responsive Images