Image Resizer - Microsoft PowerToys

Overview

Image Resizer is a Windows Shell Extension that enables quick batch resizing of images directly from File Explorer. Right-click on one or multiple images to resize them using predefined or custom dimensions without opening any image editing software.

Image Resizer preserves EXIF metadata by default and can handle multiple image formats simultaneously.

Activation

Enable Image Resizer

Open PowerToys Settings and enable Image Resizer

Select Images

In File Explorer, select one or more image files

Open Context Menu

Right-click on the selected images

Choose Resize Images

Click “Resize pictures” or “Resize images” option

Configure and Resize

Choose size preset or custom dimensions, then click Resize

Key Features

Batch Processing

Multiple Files

Resize hundreds of images at onceSelect all, right-click, resize

Mixed Formats

Process different image formats togetherJPG, PNG, BMP, TIFF, GIF, TGA

Preserve Originals

Keep original files intactCreates new resized copies

Custom Output

Choose output location and namingFlexible file organization

Size Presets

Built-in common image sizes:

Small
Medium
Large
Phone
Custom

Default: 854 × 480 pixels

Social media thumbnails
Email attachments
Quick previews

Customizable in settings

Resize Options

Multiple resizing modes:

// Resize modes available
public enum ResizeMode
{
    Fit,              // Fit within dimensions (default)
    Fill,             // Fill dimensions (may crop)
    Stretch,          // Stretch to exact dimensions
    ShrinkOnly,       // Only shrink, never enlarge
    Percentage        // Scale by percentage
}

Fit (Default)
Fill
Stretch
Percentage

Resize to fit within dimensions while maintaining aspect ratio:

Target: 1000×1000

Input: 2000×1000   →  Output: 1000×500
Input: 1000×2000   →  Output: 500×1000

Best for: Preserving image proportions

Fill target dimensions, cropping if necessary:

Target: 1000×1000

Input: 2000×1000   →  Output: 1000×1000 (cropped)
Input: 1000×2000   →  Output: 1000×1000 (cropped)

Best for: Fixed-size thumbnails

Force exact dimensions:

Target: 1000×1000

All inputs  →  Output: 1000×1000 (may distort)

Best for: When exact size is requiredWarning: May distort images

Scale by percentage:

Scale: 50%

Input: 2000×1000   →  Output: 1000×500
Input: 800×600     →  Output: 400×300

Best for: Uniform scaling

File Naming

Customizable output file names:

naming_pattern

string

default:"%1 (%2)"

Output filename patternTokens:

%1 - Original filename
%2 - Size name (e.g., “Small”, “Medium”)
%3 - Selected width
%4 - Selected height
%5 - Actual width
%6 - Actual height

Examples:

Pattern: "%1 (%2)"
Input:   photo.jpg
Output:  photo (Medium).jpg

Pattern: "%1_%3x%4"
Input:   photo.jpg
Output:  photo_1920x1080.jpg

Pattern: "%1_resized"
Input:   photo.jpg  
Output:  photo_resized.jpg

Format and Quality

output_format

enum

default:"Original"

Output image formatOptions:

Original (maintain input format)
PNG
JPEG
BMP
TIFF
GIF

jpeg_quality

number

default:"90"

JPEG compression quality (1-100)Higher = better quality, larger file size

png_interlacing

boolean

default:"false"

Enable PNG interlacing for progressive loading

tiff_compression

enum

default:"None"

TIFF compression methodOptions: None, LZW, ZIP, CCITT

EXIF Data Preservation

// EXIF metadata handling
public class ImageResizerOptions
{
    public bool KeepExifData { get; set; } = true;
    
    // Preserved metadata:
    // - Camera make/model
    // - Date taken
    // - GPS coordinates
    // - Copyright information
    // - Image orientation
    // - Camera settings (ISO, aperture, etc.)
}

Toggle in settings: Option to remove EXIF data for privacy.

Configuration

Size Presets

Customize the built-in presets:

Open PowerToys Settings
Navigate to Image Resizer
Click “Edit” on any size preset
Modify dimensions and name
Add new custom sizes with ”+”

Example custom sizes:

Instagram Square:  1080 × 1080
Facebook Cover:    820 × 312
Twitter Header:    1500 × 500
YouTube Thumbnail: 1280 × 720
4K:                3840 × 2160

Advanced Settings

shrink_only

boolean

default:"false"

Only shrink images, never enlargePrevents quality loss from upscaling

replace_original

boolean

default:"false"

Replace original files with resized versionsWarning: Cannot be undone

ignore_orientation

boolean

default:"false"

Ignore EXIF orientation flagUse if images appear rotated

output_directory

string

default:"Same as input"

Where to save resized imagesOptions:

Same folder as originals
Custom directory
Ask each time

encoder_parameters

advanced

Format-specific encoding options

JPEG: Quality, progressive
PNG: Compression level, interlacing
TIFF: Compression type

Use Cases

Web Development

Optimize Website Images

Reduce image file sizes for faster loading:

Select all images for website
Right-click → Resize images
Choose "Medium" (1366×768)
Set JPEG quality to 85%
Resize → Upload optimized images

Result: Faster page load times

Responsive Images

Create multiple sizes for responsive design:

# Create small, medium, large versions
Resize to 640px width   (mobile)
Resize to 1024px width  (tablet)
Resize to 1920px width  (desktop)

Use in HTML:

<img srcset="image-640.jpg 640w,
             image-1024.jpg 1024w,
             image-1920.jpg 1920w"
     src="image-1920.jpg" alt="...">

Photography

Social Media Sharing

Resize photos for social platforms:Instagram:

Square: 1080×1080
Portrait: 1080×1350
Landscape: 1080×566

Facebook:

Post: 1200×630
Cover: 820×312

Email Attachments

Reduce file size for email:

Select photos
Resize to “Small” or “Medium”
JPEG quality 80-85%
Attach resized versions (under 10MB total)

Print Preparation

Create print-ready sizes:

4×6”: 1800×1200 (300 DPI)
5×7”: 2100×1500 (300 DPI)
8×10”: 3000×2400 (300 DPI)

E-commerce

Product Images

Standardize product photo dimensionsConsistent sizing across catalog

Thumbnails

Create grid thumbnailsSquare format for category pages

Zoom Images

Multiple resolution versionsSmall preview + large zoom view

Mobile Optimization

Mobile-friendly image sizesReduce bandwidth usage

Content Creation

Blog Images
Presentations
Video Thumbnails

Prepare blog post images:

Featured image: 1200×630 (2:1 ratio)
Inline images:  800×600 or 800×450
Thumbnails:     400×300

Resize images for PowerPoint/Keynote:

Full slide:  1920×1080 (16:9)
Half slide:  960×1080
Quarter:     960×540

YouTube/Vimeo thumbnails:

YouTube:  1280×720 (16:9)
Vimeo:    1280×720

Technical Details

Architecture

Windows Imaging Component

Image Resizer uses Windows Imaging Component (WIC):

// WIC-based image processing
IWICImagingFactory* factory;
IWICBitmapDecoder* decoder;
IWICBitmapFrameDecode* frame;
IWICBitmapScaler* scaler;
IWICBitmapEncoder* encoder;

// High-quality resizing
scaler->Initialize(
    frame,
    newWidth,
    newHeight,
    WICBitmapInterpolationModeFant  // High-quality Fant algorithm
);

Benefits:

Native Windows support
Hardware acceleration
High-quality algorithms
Codec extensibility

Supported Formats

Format	Read	Write	Notes
JPEG	✓	✓	Adjustable quality
PNG	✓	✓	Lossless, alpha support
BMP	✓	✓	Large file sizes
TIFF	✓	✓	Multiple compression options
GIF	✓	✓	Animation preserved
TGA	✓	✓	Truevision Targa
WDP	✓	✓	Windows Media Photo
HEIC	✓	✗	Read-only (requires codec)

Resize Quality

Interpolation algorithms:

enum WICBitmapInterpolationMode
{
    WICBitmapInterpolationModeNearestNeighbor,  // Fastest, lowest quality
    WICBitmapInterpolationModeLinear,           // Fast, good for thumbnails
    WICBitmapInterpolationModeCubic,            // Good quality/speed balance
    WICBitmapInterpolationModeFant              // Highest quality (default)
};

Image Resizer uses Fant algorithm for best quality.

Project Structure

src/modules/imageresizer/
├─ ImageResizerCLI/           # Command-line interface
├─ ImageResizerContextMenu/  # Shell extension (C++)
├─ ImageResizerLib/          # Core resize logic
└─ ui/                       # Resize dialog UI (C#)

Source: src/modules/imageresizer/README.md

Keyboard Shortcuts

In Resize Dialog

Shortcut	Action
`Enter`	Resize with current settings
`Esc`	Cancel and close dialog
`Tab`	Navigate between options
`Alt+S`	Toggle size dropdown
`Alt+R`	Resize button

Troubleshooting

Context menu option not appearing

Resize fails or produces errors

Possible causes:

Insufficient disk space
Output directory not writable
Image file corrupted
Filename too long

Solutions:

Check available disk space
Verify output directory permissions
Try resizing one image to identify problem file
Use shorter filename pattern

Output images poor quality

Improve quality:

Increase JPEG quality setting (90-95)
Use PNG for lossless quality
Don’t enlarge small images
Enable “Shrink only” to prevent upscaling
Use appropriate resize mode (Fit, not Stretch)

Note: Upscaling always reduces quality

EXIF data lost after resize

Preserve metadata:

Open Image Resizer settings
Enable “Keep EXIF data”
Resize images again

Note: Some formats don’t support EXIF (BMP, GIF)Alternative: Use EXIF tools to copy metadata

Very slow for many images

Performance tips:

Process in smaller batches (50-100 images)
Close other applications
Use SSD instead of HDD
Disable antivirus temporarily
Reduce output quality slightly

Note: Processing hundreds of large RAW files takes time

Best Practices

Quality vs File Size:

Web images: JPEG 80-85 quality, 1920px max width
Thumbnails: JPEG 75 quality, 400px max
Archival: PNG lossless or JPEG 95 quality
Screenshots: PNG lossless
Photos with text: PNG or high JPEG quality

Batch Processing Tips

Test First: Resize one image to verify settings
Backup Originals: Keep original files safe
Consistent Naming: Use clear filename patterns
Organize Output: Use subfolders for different sizes
Document Settings: Note what presets/settings you used

Format Selection

Choose format based on content:

✓ JPEG:  Photos, complex images, gradients
✓ PNG:   Screenshots, logos, transparency, text
✗ BMP:   Avoid (large files, no benefits)
✓ TIFF:  Professional/archival (with LZW compression)
✗ GIF:   Avoid for photos (256 colors max)

Get Started

Core Utilities

Mouse & Input

Productivity Tools

Configuration

Community & Support

​Overview

​Activation

​Key Features

​Batch Processing

Multiple Files

Mixed Formats

Preserve Originals

Custom Output

​Size Presets

​Resize Options

​File Naming

​Format and Quality

​EXIF Data Preservation

​Configuration

​Size Presets

​Advanced Settings

​Use Cases

​Web Development

​Photography

​E-commerce

Product Images

Thumbnails

Zoom Images

Mobile Optimization

​Content Creation

​Technical Details

​Architecture

​Windows Imaging Component

​Supported Formats

​Resize Quality

​Project Structure

​Keyboard Shortcuts

​In Resize Dialog

​Troubleshooting

​Best Practices

​Batch Processing Tips

​Format Selection

​See Also

Build docs developers (and LLMs) love

Overview

Activation

Key Features

Batch Processing

Size Presets

Resize Options

File Naming

Format and Quality

EXIF Data Preservation

Configuration

Size Presets

Advanced Settings

Use Cases

Web Development

Photography

E-commerce

Content Creation

Technical Details

Architecture

Windows Imaging Component

Supported Formats

Resize Quality

Project Structure

Keyboard Shortcuts

In Resize Dialog

Troubleshooting

Best Practices

Batch Processing Tips

Format Selection

See Also