What is Aspect ratio?
The width-to-height shape of an image or video, like 9:16 for reels, 4:5 for Instagram posts or 16:9 for YouTube.
Asking for the right aspect ratio up front saves you from awkward cropping later — heads cut off, important details lost. Most image and video tools accept it directly in the prompt or as a setting.
Quick guide: 9:16 for Reels, Shorts and stories; 4:5 for Instagram feed portraits; 1:1 for profile pictures; 16:9 for YouTube thumbnails and presentations; 3:2 for a classic photo look.
In a prompt
End your image prompt with “vertical 9:16, subject centred, leave space at the top for text” when making a reel cover.
Related terms
Creating a picture from a written description. The core feature of ChatGPT images, Gemini, Midjourney and Flux.
Generating a short video clip from a written description — the technology behind Veo, Sora and Kling.
Using AI to enlarge an image and add believable detail, so a small picture looks sharp when printed or viewed full-screen.
