How do I maintain aspect ratio when resizing?

When you resize without maintaining aspect ratio, you get:

• ❌Stretched or squashed images
• ❌Distorted faces and objects
• ❌Unprofessional appearance
• ❌Circles become ovals
• ❌Text becomes unreadable

When changing width → Height adjusts automatically

When changing height → Width adjusts automatically

Both must change proportionally

Example:

• Original: 1920 x 1080
• New width: 1280
• New height: (1280 / 1920) x 1080 = 720
• Result: 1280 x 720 (same 16:9 ratio)

Resize Method 1 (Image Size):

1. Image → Image Size
2. Ensure "Constrain Proportions" (chain link icon) is ON
3. Change width OR height (other adjusts automatically)
4. Choose resampling method:

• Bicubic Sharper: For reduction (recommended)
• Bicubic Smoother: For enlargement
• Preserve Details 2.0: AI upscaling

1. Click OK

Resize Method 2 (Transform):

1. Edit → Free Transform (Ctrl/Cmd + T)
2. Hold Shift key while dragging corner
3. Shift locks proportions
4. Drag to resize
5. Press Enter

In GIMP (Free):

1. Image → Scale Image
2. Click chain link icon to lock aspect ratio
3. Change width or height (other adjusts)
4. Choose interpolation:

• Cubic: Best quality
• Linear: Faster, lower quality

1. Click Scale

In Lightroom:

1. File → Export
2. Image Sizing section
3. Choose "Width & Height"
4. Enter dimensions
5. Aspect ratio maintained automatically
6. Export

In Affinity Photo:

1. Document → Resize Document
2. Ensure "Lock aspect ratio" is checked
3. Change either dimension
4. Choose resampling:

• Lanczos 3: Best quality
• Bilinear: Faster

1. Resize

Quality Tips:

• ✅Always resize down, never up (quality loss)
• ✅Use highest quality resampling (Bicubic/Lanczos)
• ✅Resize once, not multiple times
• ✅Work from original source each time

Timeline Method:

1. Right-click clip
2. Scale to Frame Size (maintains aspect ratio, fits to timeline)
3. Or manually:

• Effect Controls → Motion → Scale
• Adjust scale percentage (maintains ratio)
• 100% = original, 50% = half size

Export Method:

1. File → Export → Media
2. Set output resolution
3. Scaling: Set to "Fit"
4. Letterbox as needed
5. Maintains aspect ratio automatically

In Final Cut Pro X:

1. Select clip in timeline
2. Video Inspector → Transform
3. Scale: Drag slider (maintains aspect ratio)
4. Or manually enter percentage
5. Use Shift + drag for proportional scaling

In DaVinci Resolve:

1. Inspector → Transform
2. Zoom: Adjusts scale proportionally
3. Or manually:

• Ensure "Link" icon is active
• Adjust Zoom X or Y
• Both adjust together

1. Export maintains original aspect ratio

For responsive images that maintain aspect ratio:

• Set width: 100% (fills container width)
• Set height: auto (adjusts automatically)
• Use object-fit: contain (maintains ratio within bounds)

Free Online Image Resizers:

• TinyPNG: Compress while maintaining ratio
• ResizeImage.net: Simple ratio-locked resize
• Canva: Resize with templates
• Photopea: Full Photoshop alternative

How to use:

1. Upload image
2. Enter new width OR height (not both)
3. Tool calculates other dimension
4. Download resized image

In Photoshop (Actions):

1. Create Action
2. Record: Image → Image Size (constrain proportions ON)
3. File → Automate → Batch
4. Apply action to folder
5. All images resize proportionally

In Lightroom:

1. Select multiple images
2. File → Export
3. Image Sizing: Set dimensions
4. Export all at once
5. Aspect ratio maintained for all

Using XnConvert (Free):

1. Add multiple images
2. Actions → Add Action → Resize
3. Choose "Keep aspect ratio"
4. Set width or height
5. Convert all

For command line batch resizing:

• Use 'magick mogrify -resize 800x *.jpg' to resize all JPGs to 800px width
• Use 'magick mogrify -resize 800x600 *.jpg' to fit within bounds
• Aspect ratio maintained automatically

• ❌Wrong:

- Drag corner without holding Shift

- Unlink chain icon in size dialog

- Manually enter both dimensions

• ✅Correct:

- Hold Shift while dragging

- Keep chain icon linked

- Enter only ONE dimension

• ❌Wrong:

- Resize 4000 → 2000 → 1000 → 500

- Each resize loses quality

• ✅Correct:

- Resize 4000 → 500 (one operation)

- Start from original each time

• ❌Wrong:

- Resize 500px to 2000px

- Adds pixels, not detail

- Looks blurry/pixelated

• ✅Correct:

- Only resize down

- Start with highest resolution source

- Use AI upscalers if absolutely necessary

• ❌Wrong:

- "Nearest Neighbor" (pixelated)

- "Bilinear" (lower quality)

• ✅Correct:

- "Bicubic" or "Lanczos" for best quality

- "Preserve Details 2.0" (Photoshop AI)

Steps:

1. Original ratio: 3:2
2. Instagram wants: 1:1
3. Must crop, not just resize!
4. Crop to 2000 x 2000 first
5. Then resize to 1080 x 1080
6. Maintains ratio during resize

Steps:

1. Original ratio: 4:3
2. New width: 300px
3. New height: (300/4000) x 3000 = 225px
4. Result: 300 x 225 (same 4:3)
5. Aspect ratio maintained

Steps:

1. Original ratio: 3:2
2. Print size: 8x12 inches (also 3:2!)
3. Set to 300 DPI
4. Final: 2400 x 3600 pixels
5. Ratio matches perfectly

Steps:

1. Original: 1920 x 1080 (16:9)
2. Target: 1280 x 720 (also 16:9)
3. Same aspect ratio!
4. Direct resize maintains proportions
5. Export at 1280 x 720

Know new width, need height:

New Height = (New Width ÷ Original Width) × Original Height

Know new height, need width:

New Width = (New Height ÷ Original Height) × Original Width

Example Calculation:

• Original: 1920 x 1080
• Want width: 640
• New height: (640 ÷ 1920) × 1080 = 360
• Result: 640 x 360

Photoshop:

• Free Transform: Ctrl/Cmd + T
• Hold Shift while dragging: Lock proportions
• Hold Alt/Option: Resize from center
• Shift + Alt: Lock proportions + center

GIMP:

• Scale Tool: Shift + T
• Chain icon: Click to lock/unlock ratio
• Enter key: Apply transformation

Video Editing:

• Shift + drag: Scale proportionally
• Alt + drag: Scale from center
• Ctrl/Cmd + Z: Undo if aspect ratio breaks

For Maximum Quality:

1. Start with highest resolution source
2. Resize once to final size
3. Use best resampling method
4. Export lossless first (PNG/TIFF)
5. Create compressed versions from lossless master

For Web:

• Resize to exact needed size
• Use sRGB color space
• Save for Web (Photoshop)
• JPG quality: 80-90%

For Print:

• Resize to 300 DPI
• 16-bit color depth
• TIFF or PSD format
• Adobe RGB or ProPhoto RGB

For responsive containers that maintain aspect ratio (like 16:9):

• Use position: relative on container
• Set width: 100%
• Use padding-bottom with percentage (e.g., 56.25% for 16:9)
• Position child elements absolutely within
• This creates a ratio-locked responsive container

Maintaining aspect ratio when resizing is simple:

1. Lock the proportions (chain icon, Shift key, etc.)
2. Change only ONE dimension (width OR height)
3. Let the software calculate the other dimension
4. Never stretch manually