The WeChat Article Cover size (900×383px)
For a WeChat Official Account, the lead article cover uses a wide 900x383 pixel image at roughly a 2.35:1 ratio. This is the banner shown at the top of the featured article when it lands in a follower's chat feed and inside the Moments and message previews, so it is the single image most responsible for whether someone taps to read. Uploading at the native size keeps the banner sharp in WeChat's in-app browser.
The important quirk is that WeChat pairs this wide top cover with smaller square thumbnails for any secondary articles in the same push. That means your cover art often needs to survive both a very wide crop for the headline slot and a tighter square crop elsewhere, so keeping the title text and main subject centered is essential. Because much of WeChat reading happens on phones in the chat stream, large, legible Chinese or English type that holds up at a glance performs far better than fine detail.
Sizing to the native 900x383 shape avoids the distortion that occurs when a square or portrait image is stretched into this cinematic slot, and it lets you control exactly what stays in the headline crop. Since Official Account content competes for attention in a busy feed, a clean, on-brand cover builds recognition push after push. This tool resizes 100% in your browser with no upload, it is free, and it preserves the aspect ratio. WeChat updates its Official Account layout and image specs from time to time, so verify the current cover size before you schedule a mass send.