Resize for Twitter/X Post

Twitter (now X) displays timeline images at a 16:9 aspect ratio, with 1600x900 pixels being the optimal upload resolution. The platform supports images up to 4096x4096 pixels and 5MB for standard uploads (16MB via API), but images are always resized to fit the timeline card, which renders at approximately 510x287 pixels on desktop and full-width on mobile. Uploading at 1600x900 provides enough resolution for both the timeline preview and the expanded lightbox view where users can see the image at near-original quality.

Twitter's image processing compresses uploads to JPEG regardless of input format, with one notable exception: PNG images under 900x900 pixels with fewer than 256 colors are preserved as PNG, which is useful for screenshots and graphics with text. For photographs and complex images, Twitter's JPEG compression is moderate but noticeable on gradients and sky backgrounds. The platform applies different compression levels based on the image content — high-detail images get less compression than simple graphics. Images are also stripped of all EXIF data including geolocation.

The Twitter timeline crops images to 16:9 from the center by default, though Twitter's machine learning-based saliency detection attempts to identify the most interesting region and crop accordingly. This means faces and high-contrast areas usually survive cropping, but you should not rely on this behavior for critical content. The safest approach is to design at exactly 16:9 with essential elements centered. When posting multiple images, the crop ratios change: two images crop to 7:8 each, three images use one 7:8 and two 4:7 panels, and four images crop to four equal rectangles.

A key mistake on Twitter is over-designing images with too much information. Twitter is a fast-scrolling platform where images compete with dense text content. The most engaging post images have a single clear focal point, minimal text (under 10 words), and high color contrast. Avoid thin fonts, detailed infographics, and complex charts in timeline images — these work better as linked content. Also note that animated GIFs on Twitter are heavily compressed and limited to 15MB, often resulting in significant quality degradation.