X timelines mix text, images, polls, and video. For still images, your goal is simple: no accidental letterboxing, no unreadable microtext, and no surprise carousel crops.
Single-image posts (starting points)
| Aspect | Pixels (example) | When to use |
|---|---|---|
| 16:9 | 1200 × 675 | Product hero shots, event banners, screenshots with UI chrome |
| 1:1 | 1080 × 1080 | Illustrations, memes, portraits, carousel tiles |
| 4:5 (portrait) | 1080 × 1350 | Vertical artwork when you accept feed crop differences |
Multi-image layouts change the math
X rearranges grids when you attach 2–4 images. Rules of thumb:
- Keep faces and logos near the center third.
- Avoid ultra-thin strokes-they moiré when compressed.
- Export each tile at similar sharpness so the set looks cohesive.
Compression & artifact control
High-frequency noise (film grain, grass, confetti) explodes after platform encodes. mild blur on backgrounds or slightly lower saturation can preserve subject edges.
Video is a different product surface
Images do not share the same constraints as native video. Review X video help when you cross-post 16:9 masters.
Copy & CTA pairing
Do not hide refunds, pricing, or legal terms only inside the pixels. Repeat key terms in the post body so searchers and screen readers get the full message.
Research rabbit hole
If you source inspiration via search operators, bookmark advanced search recipes instead of relying on default keyword chatter.
Frequently asked questions
- What is the best image size for X (Twitter) posts?
- For single landscape cards, ~1200×675 (16:9) is a strong default. Square 1080×1080 also works well. Always preview because multi-image layouts change crops.
- What file size should X images be?
- Stay conservative (often ≤5 MB per image on many clients) to reduce forced compression. If uploads fail on mobile, re-export as slightly lower quality JPG.
- Does X support alt text?
- Yes-add concise, non-keyword-stuffed descriptions when the UI offers alt text. It helps accessibility and clarifies intent if images fail to load.
- How long can videos be on X?
- Standard accounts face short limits and a 512 MB cap for typical uploads; X Premium may unlock much longer uploads. Check help.x.com before shipping long clips.