What is the actual dimension of cover image?

[site2017]

Twitter's cover image spec is locked at 1500 pixels wide by 500 tall - non-negotiable for avoiding those pesky moiré patterns and JPEG artifacts post-upload. Stick to RGB color mode, sRGB profile, and cap file size at 5MB to prevent server-side throttling. Use batch processing in GIMP or Lightroom to upscale low-res originals; it'll preserve sharpness across devices.