Social media image sizes: when to use 3:4, 4:5, 1:1, and 9:16
Choosing a social media image size is more than cropping. Learn when 3:4, 4:5, 1:1, and 9:16 fit your content, and how to keep layouts readable after export.
Image dimensions change how information is read. Cropping the same copy from 3:4 into 1:1 can break title lines, crowd the body, or cut off the relationship the layout was explaining. Choose the size after the content structure is clear, not as an arbitrary final export setting.
3:4: for content carousels and knowledge images
3:4 is a balanced vertical ratio for content-led images. It gives titles, body copy, and relationship structures enough room, making it a good fit for article carousels, knowledge cards, tutorials, and case reviews. When an image has several layers of information, it is usually more forgiving than a square canvas.
4:5: for concise social images and content-led posters
4:5 is still vertical but more compact than 3:4. It works for one central conclusion, a cover, a short list of points, or a promotional image. Do not force dense source material into 4:5 only because a platform uses it often; add images or use a denser structure instead.
1:1: for shorter, clearer single points
Square images work well for one main idea, one data comparison, a product note, or a social cover. They are not ideal for complete article summaries unless the source is very short or has already been reorganized into a few high-value blocks.
9:16: for full-screen distribution, not every article
9:16 works well for full-screen stories, short-video covers, and vertical feeds. It can hold a lot of content, but reading becomes more linear. For a knowledge map with complex relationships, an overly tall canvas can force readers to scroll; a carousel or 3:4 card may be easier to absorb.
Check the layout, not only the dimensions
For every ratio, confirm that titles still have hierarchy, body copy is readable on a phone, numbers are not crowded against an edge, and every page has a clear focal point. A dimension change should trigger a layout recalculation too.
In the social media image generator, choose the final image count first, then export in 3:4, 4:5, 1:1, 9:16, or a custom size.