Best Image Sizes for RedNote, Instagram, Pinterest, TikTok, Reels and Shorts
Publishing the same visual everywhere sounds simple until each platform asks for a different crop. A square-ish image that works on one feed can lose its subject on a vertical short-form cover. A tall product image can look cramped inside a 4:5 post. The goal of AI image expansion is to keep the important subject visible while extending the surrounding background into the format each platform needs.
This guide covers the core ratios currently supported by ImageFit AI and when to use each one.
RedNote 3:4
Use 3:4 when you want a vertical image that still feels like a feed post, not a full-screen video cover. It is useful for lifestyle images, outfit photos, product shots and notes where the image needs room for context.
3:4 is usually a good first target when your original image is close to portrait orientation. The expansion area is moderate, so the model has less new background to invent than it would with 9:16.
Best for:
- RedNote cover images
- Product and lifestyle posts
- Portrait photos that need more vertical room
Instagram 4:5
4:5 is a reliable feed format because it gives more vertical space than a square while still fitting naturally in a scrolling layout. It is often the safest option when your original photo already looks good but needs a cleaner platform-ready crop.
For product images, 4:5 can preserve detail without making the subject feel tiny. For people or places, it gives the image a stronger presence than 1:1.
Best for:
- Instagram feed posts
- Portfolio images
- Product previews and creator content
Pinterest 2:3
Pinterest favors taller visuals. 2:3 gives more vertical room and can make covers more discoverable in a visual search or inspiration board context.
Because 2:3 needs more expansion than 4:5, start with a clear subject and enough original background for the AI to understand the scene. If the subject touches the edge of the image, review the candidates carefully.
Best for:
- Pinterest pins
- Inspiration boards
- Tutorial and product visuals
TikTok, Reels and Shorts 9:16
9:16 is the most aggressive target because it fills a vertical mobile screen. It is ideal for short-form cover images, but it also requires the most new background. That means the source image matters more.
Choose 9:16 when the subject is clear and you want a full vertical cover. If your original is landscape or tightly cropped, generate multiple candidates and compare them before downloading.
Best for:
- TikTok covers
- Instagram Reels covers
- YouTube Shorts thumbnails
- Vertical campaign images
A practical workflow
Start with the platform where the image matters most. Generate one or three candidates, then inspect the subject, background continuity and any text-sensitive areas. If you need to publish everywhere, create the closest ratio first, then generate the more dramatic vertical versions.
ImageFit AI is designed for this workflow: upload one image, select a target platform ratio, review the candidates and download the version that fits your post.
