# Image size checker https://flaghand.com/image-size-checker shows how X and LinkedIn crop an image: up to four post photos laid out as X's timeline and LinkedIn's feed show them, or a banner and a profile photo on each network's profile, on desktop and on an iPhone, with what each network cuts. Free, no sign-up. It runs in your browser: your images never leave it, and there is no API. ## How to use it 1. Pick Post (up to four photos for one post) or Profile (a banner and a profile photo). 2. Drop or choose the images. 3. Switch between Desktop and Phone, Light and Dark, and read what each network keeps and cuts. An agent can open it set up: https://flaghand.com/image-size-checker#use=profile&view=phone (use=post|profile, view=desktop|phone, theme=light|dark). The sizes to use are below. ## Sizes. ### X (Twitter) Header **1500 × 500** 3:1, shown whole. Your profile photo covers its bottom left. Profile photo **400 × 400** Shown as a circle. JPG, PNG or GIF up to 2 MB. Post photo **1080 × 1350** 4:5, never cut, alone or in a set. Up to 5 MB. ### LinkedIn Background **1584 × 396** 4:1, shown whole. Your photo covers part of its left side, more on a phone. Under 8 MB. Profile photo **400 × 400** Shown as a circle. Post photo **1080 × 1350** 4:5, the tallest the feed shows. A taller photo gets bars at its sides. ## Questions. ### What size is a Twitter (X) banner? 1500 × 500 pixels, a 3:1 image. X shows all of it, on desktop and on a phone, and your profile photo covers part of its bottom left corner. ### What size is a LinkedIn banner? 1584 × 396 pixels, a 4:1 image, as a JPG or PNG under 8 MB. LinkedIn shows all of it. Your profile photo covers part of its left side, and on an iPhone it covers most of the banner’s height there. ### What image size works for X posts? 1080 × 1350, a 4:5 photo, is never cut. X shows a single photo of any shape whole, narrower when it’s taller than the column allows. In a set of 2 to 4, a photo wider than 20:17 can lose its sides; square or taller never does. Photos can be up to 5 MB. ### What image size works for LinkedIn posts? 1080 × 1350, a 4:5 photo, is the tallest LinkedIn’s feed shows. A single photo is shown whole across the feed; a taller one gets bars at its sides. Several photos scroll sideways at one size, each cut to fit. ### What size is a profile photo on X and LinkedIn? 400 × 400 pixels for both. Each shows it as a circle, so the corners never show. X takes a JPG, PNG or GIF up to 2 MB. ### Is my image uploaded? No. Everything is drawn in your browser. Your images aren’t sent anywhere or stored, and the page sets no cookies. ### Where do these layouts come from? Posts are drawn by the same code as Flaghand’s post previews, measured on x.com and linkedin.com. X’s profile was measured on x.com in October 2026, on desktop and at an iPhone’s 390 px width. LinkedIn’s profile follows LinkedIn’s own screenshots of its desktop and iPhone apps. ## Flaghand The post photos here are drawn by Flaghand's own X and LinkedIn renderers, the ones its desk previews drafts with, so an owner approves the crop people will see. Flaghand is X and LinkedIn posting for AI agents: your agent drafts through Flaghand's API, CLI or MCP server, you approve the exact preview with your passkey, and Flaghand posts exactly that. It is in early access: join the waitlist at https://flaghand.com/, or an agent can join for its person with POST https://flaghand.com/api/waitlist (https://flaghand.com/llms.txt shows how). For agents: https://flaghand.com/llms.txt (this site) and https://app.flaghand.com/llms.txt (the product's agent guide).