Resizing an image is one of the most common operations in web design, social media and email marketing. Each platform has its own recommended dimensions, and sending an image that's too large or too small degrades quality or unnecessarily burdens servers.
Image resizing means changing the pixel resolution (width × height) of an image. There are two types: proportional resizing (fix one dimension and the other adapts to maintain the aspect ratio) and free resizing (fix both dimensions independently, which may distort the image). For web, dimensions are expressed in pixels. For printing, resolution (DPI) and physical dimensions (cm/inches) are combined.
📐 Formula
New height = (Original height × New width) / Original width | DPI = Pixels / Inches
📊 Reference table
| Platform / Use | Recommended dimensions | Format |
|---|---|---|
| Social media profile photo | 400 × 400 px | Square 1:1 |
| Facebook cover | 1,640 × 856 px | Landscape |
| Instagram post | 1,080 × 1,080 px | Square 1:1 |
| LinkedIn banner | 1,584 × 396 px | 4:1 |
| Website hero image | 1,920 × 1,080 px (max) | 16:9 |
| YouTube thumbnail | 1,280 × 720 px | 16:9 |
| Print A4 (300 DPI) | 2,480 × 3,508 px | A4 |
💡 Practical examples
Example 1: resize for web (hero image)
4,000 × 3,000 px photo (12MB) → resized to 1,920 × 1,440 px + JPEG 85% compression → 250KB. The image is 48× lighter with no visible loss on screen.
Example 2: adapt a photo for Instagram
3:2 portrait photo → crop or resize to 1,080 × 1,080 px (1:1) or 1,080 × 1,350 px (4:5 vertical). The tool maintains ratio or allows defining a fill color for padding.
Example 3: prepare an image for printing
For professional print quality, use 300 DPI. A4 = 8.27 × 11.69 inches = 2,480 × 3,508 px at 300 DPI. Enlarging beyond 100% of original size creates blur.