AI image social media size guide
Every platform has its own ideal image dimensions, and getting them wrong means blurry uploads, awkward crops, or rejected ads. This guide lists the current optimal sizes for Instagram, Twitter/X, LinkedIn, Facebook, Pinterest, TikTok, and YouTube, broken down by post type, and gives you a one-click prompt suffix that tells your AI image generator the right aspect ratio and dimensions.
How it works
Pick a platform and a post type, and the tool shows the recommended pixel dimensions and aspect ratio. Because diffusion models respect aspect ratio more reliably than exact pixel counts, the generated prompt suffix leads with the ratio (for example “9:16 vertical, 1080×1920”) so the model frames the composition correctly. You then upscale and crop to the exact spec, which is far cleaner than fixing proportions after the fact.
Dimensions at a glance
| Platform | Format | Size | Ratio |
|---|---|---|---|
| Feed square | 1080×1080 | 1:1 | |
| Feed portrait | 1080×1350 | 4:5 | |
| Story / Reel | 1080×1920 | 9:16 | |
| Twitter/X | In-stream image | 1600×900 | 16:9 |
| Feed post | 1200×627 | ~1.91:1 | |
| Feed photo | 1200×630 | ~1.91:1 | |
| Standard pin | 1000×1500 | 2:3 | |
| TikTok | Video cover | 1080×1920 | 9:16 |
| YouTube | Thumbnail | 1280×720 | 16:9 |
These are the platform-recommended sizes at time of writing. Platforms occasionally update their specs; always verify with the platform’s official creator documentation for paid ad formats before a campaign launch.
Where AI generation goes wrong
AI image models are optimized for common aspect ratios like 1:1 or 16:9. Ask for an unusual size like 4:5 and most models will either ignore it, produce the closest supported ratio, or generate distorted output. The workflow that avoids this:
- Prompt for the ratio, not the pixel count — write
4:5 portrait orientationin your prompt. - Generate at the highest supported resolution to maximize detail before resizing.
- Upscale with a dedicated tool (many models include a built-in upscaler) to reach the exact platform pixels.
- Crop precisely as a final step, not at generation time.
Platform-specific cautions
- Instagram feed: the 4:5 portrait ratio gives you the most screen real estate in the feed scroll; square (1:1) is safe but shows smaller.
- YouTube thumbnails: keep all key text and faces away from the bottom-right 15% of the image — that corner is covered by the video duration badge on most devices.
- Stories / Reels / TikTok: the top ~200 pixels and bottom ~350 pixels can be obscured by UI overlays (username, description, share buttons). Keep all critical content in the central safe zone.
- LinkedIn: the feed image is shown at a fixed container width; landscape images show more prominently than portrait ones here.
Tips for platform-perfect AI images
- Match the ratio at generation time. A 1:1 prompt for a square post saves you from cropping faces or text out of a wide image.
- Leave safe margins. Stories and Reels overlay UI on the top and bottom; keep critical content in the central area.
- Upscale, then crop. Generate at the nearest supported size, upscale, and crop last to land on the exact pixel dimensions.
- Mind the duration stamp. On YouTube thumbnails, avoid placing key elements in the bottom-right corner.
- Test on mobile. Upload a test image and view it on a real phone before scheduling — compression and color rendering vary between devices.