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Social media size cheat sheet (2026 edition)
Every platform automatically compresses and crops uploads that don't match their expected dimensions. Use the presets built into the resizer to hit the exact target first time:| Platform | Type | Dimensions |
|---|---|---|
| Square Post | 1080 × 1080 px | |
| Portrait Post | 1080 × 1350 px | |
| Stories / Reels | 1080 × 1920 px | |
| YouTube | Thumbnail | 1280 × 720 px |
| Banner | 1584 × 396 px | |
| X (Twitter) | Header | 1500 × 500 px |
| X (Twitter) | Timeline Image | 1200 × 675 px |
How the resizer works under the hood
The tool draws your image onto an HTML Canvas element at the target dimensions using Lanczos-3 resampling. This is a sinc-based interpolation filter with a 3-lobe window that calculates each new pixel by sampling a weighted neighbourhood of surrounding source pixels.Why does this matter? Compare the three common algorithms:
- Nearest-neighbour: Fast, but produces blocky staircasing artifacts on diagonal edges.
- Bilinear: Smooth, but blurs fine details — especially bad for screenshots with text.
- Lanczos-3: Preserves sharpness on downscale by applying a mathematically optimal weighting curve. Text and line art stay crisp; photo edges stay clean.
How to use the Image Resizer
- Upload your image — Drop a PNG, JPEG, or WebP file. The tool reads and displays the original dimensions before you make any changes.
- Set target dimensions — Type in pixel values, or select a social media preset. Toggle 'Lock Aspect Ratio' to scale proportionally.
- Resize and download — The canvas renders the resampled image. Click Download to save in the same format as your source.
Tips for best results
- Downscaling: Always better quality than upscaling. If you have a 4K photo and need a 1080×1080 thumbnail, the Lanczos output will be sharp.
- Upscaling small images: No algorithm can invent pixels that don't exist. For 2× enlargements or more, consider using a dedicated AI upscaler first.
- PNG logos: Aspect ratio lock is critical — a 512×512 icon resized to 200×150 without lock will look squished. Always keep the lock enabled for logos.