Social media and platform image sizes

The reason to do this in one pass is that the crops disagree with each other. A 9:16 story and a 1.91:1 link preview cannot both keep the edges of the same design, so the only image that survives every placement is one whose important content sits in a centred square. Check the set after exporting rather than assuming: it is common for a design that looks fine at 1200 × 630 to lose a logo entirely at 1080 × 1920. What follows is the part the dimensions do not tell you, grouped by the kind of placement rather than by platform, because the traps repeat.

Vertical: the interface owns both ends

Every vertical placement here is 1080 × 1920, and every one of them lays its own chrome over yours. Instagram covers roughly the top 14 percent with the profile row and the bottom 20 with the reply bar. A Reel takes more at the bottom for the caption and a strip down the right for the like, comment, share and audio buttons, and its cover is never shown at 9:16: the feed crops it to 4:5 and the profile grid to a centred 3:4 tile, so cover text has to survive both. TikTok takes more again, and its own auto-captions land in the same crowded bottom area, which is why burning your subtitles higher in the frame is the reliable fix rather than hoping the platform places them somewhere sensible. WhatsApp is the gentlest, roughly the top tenth and the bottom fifth, and the harshest on quality: a status is recompressed hard, so bold shapes survive and fine detail does not. Snapchat keeps the bottom fifth for the attachment call to action, and a Spotify Canvas gives up the bottom third to the player controls.

Two limits here are not pixels at all. An Instagram Reel runs to three minutes at most. TikTok accepts up to 287.6 MB uploaded from the iOS app and 72 MB from Android, with more allowed through the web uploader, and it letterboxes a landscape upload with bars that consistently underperform against native vertical.

Avatars are judged at display size

Upload a 320 or 400 pixel square and the file is fine. The number that decides whether the avatar works is the size it is rendered at, and it is far smaller than most people picture. Facebook shows one at 176 on a desktop profile, 128 on mobile and 40 pixels in a comment thread. Instagram shows one at 110 on a profile and 32 beside a post. TikTok shows one at roughly 48 in the feed, with the follow button overlapping its lower edge. All of them mask the square to a circle, so the corners go too. At 32 pixels a wordmark is a grey smudge; a single face, one letter or one solid shape is what reads. Podcast artwork has the same problem from the other direction. You supply 3000 square, a directory listing shows about 300, and the now-playing bar shows 55, so the large file exists for a view almost nobody opens.

Link previews come from the page, not from an upload

The Open Graph image is the one picture on this list you never upload anywhere. Facebook, LinkedIn, WhatsApp, Slack, Discord and X all read og:image from the page being linked to, which is why two failures are more common than a wrong size. A relative URL fails silently, because scrapers do not resolve it. And Facebook caches what it fetched, so a corrected tag changes nothing until the URL is re-scraped in the Sharing Debugger. X departs from the pattern once there is more than one image: a single picture shows at 16:9 uncropped, two sit side by side with each cropped to a tall half, and four become a 2 × 2 grid of squares, so a 16:9 that looks right alone loses its sides the moment a second one joins it.

Headers and banners are the extreme ratios

These are the placements where the shape itself is the constraint. An X (Twitter) header is 3:1 with your avatar over the lower left, and mobile shows a shorter slice than desktop, so the vertical centre is the only reliably visible band; X is also harsher on JPEG than on PNG, so a header of flat colour and type holds up better as a PNG under the 5 MB limit. LinkedIn uses two different strips, 1584 × 396 on a personal profile against 1128 × 191 on a company page, which is nearly 6:1. A subreddit banner is 5:1 at the large height, and a phone shows only a central portion of that width, which is why the circular icon, shown at one consistent size everywhere, is the more reliable place to put identity. Reddit’s help pages state a floor rather than a target here — at least 1072 × 128 on desktop, 1080 × 128 in the apps — and uploading the floor is how a banner arrives soft on a wide screen; export 1920 × 384 and let Reddit come down from it. Discord gates its banners on boost level and Nitro rather than on pixels. Twitch has the one banner people actually look at: the offline player image, which fills the player whenever you are not streaming.

Marketplaces regulate content, not only pixels

No cropper can fix this group, because the rules are about what is in the frame. An Amazon main image has to be on pure white at RGB 255, 255, 255, with the product filling at least 85 percent, and no text, logos, watermarks, borders, props or inset images; Amazon enforces it by suppressing the listing. eBay bans the same additions on a main photo, along with stock photographs standing in for used goods. Both disable zoom below 1600 pixels on the longest side, and zoom is exactly what a buyer uses to judge condition. Etsy crops your square first image to a 5:4 landscape for the search thumbnail, taken from the middle, so the top and bottom disappear in the one place shoppers are choosing between listings. Shopify generates its own resized copies, so uploading 2048 costs the store nothing, and a collection grid looks unfinished when some products were shot square and others portrait.

Email is the oldest constraint here

Six hundred pixels wide, unchanged for two decades because it fits the narrowest preview panes. Export at 1200 and set the HTML width attribute to 600 so it stays sharp on a high-density screen. The bigger problem is not the width: many clients block images by default, so a header carrying the whole message arrives as a blank rectangle and the alt text is all the reader gets. Several clients invert backgrounds in dark mode, which makes a logo saved as black on transparent vanish, so give it a background of its own. And several clip a message that grows too large, which is the reason to keep the header itself under about 200 KB.

Where these numbers come from

Most of these figures come from the platforms’ own published specifications and were checked on the review date shown. Some are not published anywhere: the size an avatar is rendered at, and the exact share of a vertical frame an interface covers, are measured rather than documented, and several placements were added to this page after that date. Platforms change both without announcing it, so treat a spec that looks wrong as worth verifying rather than as gospel.