AI Image Sizes for Every Social Platform (2026 Guide)

I learned this lesson the embarrassing way. I once generated a gorgeous vertical poster, posted it to Instagram, and watched the app crop the top and bottom off — the headline art I'd spent twenty minutes perfecting just vanished. The image wasn't bad. The size was wrong. And that's the thing nobody tells you when you start generating images for social media: the platforms don't care how good your art is if it doesn't fit their frame. A size mismatch turns a great image into a blurry crop, a black-barred thumbnail, or a pin nobody clicks. So I keep one cheat sheet on my desk, and this is it — the sizes I actually generate at, with the mistakes I've already made for you.

Before the platform-by-platform list, here's the habit that saves everything else. Always generate at the largest size your tool allows, and always in the aspect ratio closest to your target. Upscaling a small image makes it soft; cropping a big one costs nothing. My rule of thumb: if I'm not sure where an image will end up, I generate it at 9:16 vertical — that's the tallest common frame, so it holds the most picture to crop from later. Then I make the platform versions from that master, never from a version that was already cropped once. Every re-crop of a crop loses a little more of the scene, and by the third platform you're posting a postage stamp of the original idea.

Instagram is the pickiest platform in this list, because it genuinely uses three different frames and treats each one differently. Square posts are 1080 x 1080 (1:1) — safe, classic, and honestly the least interesting option now. Portrait posts are 1080 x 1350 (4:5), and this is the one I'd pick for feed posts most days: it takes up more screen height as people scroll, so it stops thumbs better than a square. Stories and Reels covers are 1080 x 1920 (9:16), full phone screen. The trap here is the safe zone. Instagram's own interface eats the top and bottom of a Story — profile picture, reply bar, buttons — so keep anything important in the middle 70% of the frame. I once put a product at the very bottom of a Story image and the reply bar sat right on top of it for the whole 24 hours. Center your subject, leave breathing room, and you'll never have that problem.

• Feed square: 1080 x 1080 (1:1) — safe but smallest on screen.
• Feed portrait: 1080 x 1350 (4:5) — my default for feed posts; biggest scroll presence.
• Story / Reel cover: 1080 x 1920 (9:16) — keep key details in the middle 70%, away from top and bottom bars.
• Profile picture: 320 x 320 displayed in a circle — generate with the subject centered, because the corners get cut off.

YouTube thumbnails are 1280 x 720 (16:9), and here's the part people get wrong: a thumbnail is not a small poster. At the size viewers actually see it — a rectangle about as wide as two fingers on a phone — fine detail disappears completely. A thumbnail that looks stunning at full size can read as grey mush in the feed. So when I generate a thumbnail, I ask for one big subject, one strong color contrast, and almost no background clutter. Three elements, maximum. Test it yourself: shrink your thumbnail to the size of a matchbox on your screen. If you can't tell what it is in one second, simplify it. Channel banners are a separate headache at 2560 x 1440, but only the middle strip (about 1546 x 423) is guaranteed visible on every device — TVs show the whole thing, phones show that strip. Put your name and tagline in the strip, decoration everywhere else.

These three all love wide images, but the exact widths differ just enough to trip you up. A shared Facebook post image works best at 1200 x 630 (about 1.91:1) — that's the size that fills the link preview nicely instead of leaving a sad small box. Facebook cover photos are 851 x 315 on desktop, but phones crop the sides, so again, center the important stuff. X posts look sharpest at 1600 x 900 (16:9), and X headers are 1500 x 500 — but your profile photo sits over the bottom-left corner of the header, so don't put anything precious there. LinkedIn shared images are 1200 x 627, practically the same as Facebook's, which is handy: one 1200 x 630 master usually serves both without a visible difference. If you only have time to make one wide version, make it 1200 x 630 and use it on both.

• Facebook post / link preview: 1200 x 630 — the workhorse wide size.
• Facebook cover: 851 x 315 desktop, sides cropped on mobile — center your message.
• X post image: 1600 x 900 (16:9); X header: 1500 x 500, with the profile photo covering the bottom-left.
• LinkedIn post image: 1200 x 627 — close enough to Facebook's size to share one master file.

Pinterest is the opposite of the wide-image club. Its feed is a tall masonry grid, and tall pins win — the standard is 1000 x 1500 (2:3). A square pin in that grid just looks small next to everything else, and Pinterest itself warns that images taller than 2:3 get cropped in the feed, so don't go crazy with extra height either. 2:3 is the sweet spot; anything between that and square works, but 2:3 is what I'd generate. TikTok is full-screen vertical like Instagram Stories: 1080 x 1920 (9:16), and the same safe-zone rule applies — the caption sits bottom-right, the buttons run down the right edge, so keep your subject left-of-center or middle. One nice bonus: a good 9:16 master covers TikTok, Reels, Shorts, and Stories in one file, which is why I start there when I'm unsure.

Here's how this turns into a real routine instead of a spreadsheet you never open. I generate one master image at the biggest size available, usually 9:16. Then I export four versions: the 9:16 original for Stories, Reels, Shorts, and TikTok; a 4:5 crop (1080 x 1350) for the Instagram feed; a 2:3 crop (1000 x 1500) for Pinterest; and a 16:9 crop (1280 x 720) for YouTube thumbnails and X. Four exports, about two minutes in any free editor, and the same image now fits everywhere without a single awkward auto-crop. The one thing I check on every export: is the subject still fully in frame? Cropping from vertical to wide is where heads and products get sliced in half, and if the wide crop amputates the subject, I regenerate that version with a wider prompt instead of forcing it.

• Generate one big master, ideally 9:16, at your tool's highest resolution.
• Export 9:16 for Stories/Reels/Shorts/TikTok, 4:5 for Instagram feed, 2:3 for Pinterest, 16:9 for YouTube and X.
• After every crop, check the subject is fully in frame — never let a crop cut a head or product in half.
• Save each platform version as its own file (name it with the platform) so you never re-crop a crop.
• Keep text out of generated images where possible; add captions in the platform's own editor so they stay sharp.

First, generating at the exact small size instead of larger and cropping down — a 1080-pixel image upscaled for a banner turns to mush, but a 2048-pixel master downscaled to anything stays crisp. Second, trusting the platform preview: previews lie, because they show your image in the upload screen, not in the feed next to other posts. Always check the published post on your phone. Third, forgetting file size: huge PNG masters are fine for editing, but for posting, a JPG under a couple of megabytes uploads faster and looks identical on a phone screen. I export posting copies as JPG, keep the big master separately, and never mix the two up. Get the size right once and your images stop fighting the platform — they just show up the way you made them.