In the X timeline a 16:9 image spans the full width of the screen and noticeably lifts engagement. The maker creates a landscape, a square and a profile header from one idea.
X (Twitter) formats in the maker: landscape post 1600×900, post 1080×1080, header 1500×500. Tick the ones you need and choose how many picture variants to make for each, from one to four.
Your avatar covers the bottom-left of the 1500×500 header, so a short tagline works best there. For announcements, write several copy versions and rotate them from post to post.
Pictures are drawn by GPT Image 2.5, Nano Banana, Seedream or FLUX; you pick the model before you start. For shapes the main picture doesn't have, the AI extends its edges, so nothing important gets cropped.