Platforms re-encode everything you upload. If your image already matches the recommended dimensions and aspect ratio, that re-encode is gentle; if it doesn't, you get aggressive cropping, stretching or blur. Here are the numbers that matter in 2026.
The Cheat Sheet
- Feed post (square): 1080 × 1080 (1:1)
- Feed post (portrait): 1080 × 1350 (4:5) — takes the most screen space
- Stories / Reels: 1080 × 1920 (9:16)
- Shared post image: 1200 × 630 (1.91:1)
- Cover photo: 820 × 312 (desktop display)
X (Twitter)
- In-stream image: 1600 × 900 (16:9)
- Header: 1500 × 500 (3:1)
- Shared image: 1200 × 627 (1.91:1)
- Personal banner: 1584 × 396 (4:1)
YouTube
- Thumbnail: 1280 × 720 (16:9), must be under 2 MB
- Channel banner: 2560 × 1440 (safe area ~1546 × 423)
WeChat / Red Note (Xiaohongshu) / Douyin
- WeChat official account cover: 900 × 383 (2.35:1)
- Xiaohongshu cover: 1242 × 1660 (3:4)
- Douyin / TikTok video cover: 1080 × 1920 (9:16)
The Two-Step Workflow: Resize, Then Crop
Uploading a 6000 px camera photo and letting the app "figure it out" is how images get ruined. Do it yourself in two steps:
- Crop to the target aspect ratio first. Use a crop tool with a fixed ratio (1:1, 4:5, 16:9…) so you control what gets cut — keep faces and text inside the middle 80% of the frame.
- Resize down to the exact target pixels. Downscaling is safe and keeps things sharp. *Upscaling* a too-small image is what causes blur — if your source is smaller than the target, start from a bigger original instead.
Both steps run in seconds in a browser-based Crop Image and Resize Image tool, with no app install.
One Last Trap: File-Size Limits
Some platforms also cap the file weight (YouTube thumbnails: 2 MB). If your perfectly-sized PNG is too heavy, compress it to a target size — a 1280 × 720 thumbnail looks identical at 300 KB as a JPEG around quality 85.
Sizes drift as platforms redesign, but aspect ratios are sticky: master 1:1, 4:5, 9:16, 16:9 and 1.91:1 and you cover practically every feed on the internet.