Substack Image Sizes — Newsletter Header, Logo & Post Hero Dimensions
Substack renders the same image in two very different places: the web post (wide, retina-friendly) and the inbox email (narrow, capped at ~728px). Uploading at the right source size lets Substack’s auto-resize pipeline produce both versions without the inbox copy turning soft or the web copy looking pixelated on retina screens.
All Substack Dimensions
Newsletter Header / Post Hero
- 1456 x 816 — Recommended source (~16:9)
- ~728 x 408 — Rendered size in inbox email
- Formats: JPG, PNG, GIF, WEBP
Publication Logo
- 256 x 256 — Minimum, 1:1 square
- Cropped to a rounded square / circle depending on surface
Profile Photo
- 256 x 256 — Author profile (1:1)
- Cropped to a circle on web and email
Inline Body Images
- Render at content width — ~640px in email, ~720px on web
- Upload at 2x (1280–1440 wide) for retina sharpness
- Substack auto-resizes both versions on upload
Substack Image Specs Comparison
| Asset | Upload Size | Rendered (Inbox / Web) | Aspect Ratio |
|---|---|---|---|
| Newsletter header | 1456 x 816 | 728 x 408 / full width | ~16:9 |
| Post / section hero | 1456 x 816 | 728 x 408 / full width | ~16:9 |
| Publication logo | 256 x 256+ | ~64 x 64 in header | 1:1 |
| Profile photo | 256 x 256 | ~48 x 48 in byline | 1:1 |
| Inline body image | 1280–1440 wide | ~640 / ~720 | Any |
Substack Image Optimization Tips
- Upload at 2x the rendered size: Substack’s auto-resize pipeline produces a sharp version for retina inboxes if you give it enough source pixels. Upload headers at 1456x816 and inline images at 1280–1440 wide so the 2x and 3x retina derivatives stay sharp.
- Don’t upload at the rendered size: a 728x408 header upload renders blurry on retina inboxes because Substack has no extra resolution to work with. Always work from a larger master and let Substack downscale.
- Email caps bandwidth, not dimensions: Gmail clips Substack emails over ~102KB total. A heavy header image pushes the rest of the email below the clip line. Compress with mozJPEG or convert to WebP where supported.
- Test the email preview, not just the web post: the inbox version is what most subscribers see. Send a test email to yourself before publishing — fonts, image sharpness, and dark-mode rendering all behave differently in Gmail, Apple Mail, and Outlook.
- Logos crop differently in different surfaces: Substack uses your 256x256 logo as a rounded square in some headers and a circle in others. Keep the focal element centered with at least 10% padding.
- Animated GIFs are allowed but heavy: Substack supports GIF in headers and bodies, but every animation frame ships in the email. A 5MB GIF can blow past the inbox clipping line single-handedly — use sparingly.
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Social Media Image Size Cheat Sheet (2024)
| Platform | Type | Dimensions |
|---|---|---|
| Post (Square) | 1080 x 1080 | |
| Post (Portrait) | 1080 x 1350 | |
| Post (Landscape) | 1080 x 566 | |
| Story / Reel | 1080 x 1920 | |
| Profile Photo | 320 x 320 | |
| TikTok | Video Cover | 1080 x 1920 |
| Profile Photo | 200 x 200 | |
| YouTube | Thumbnail | 1280 x 720 |
| Channel Banner | 2560 x 1440 | |
| Profile Photo | 800 x 800 | |
| Post (Landscape) | 1200 x 630 | |
| Post (Square) | 1200 x 1200 | |
| Cover Photo | 820 x 312 | |
| Profile Photo | 170 x 170 | |
| Event Cover | 1200 x 628 | |
| X (Twitter) | Profile Photo | 400 x 400 |
| Header Photo | 1500 x 500 | |
| In-Stream Photo | 1600 x 900 | |
| Card Image | 1200 x 628 | |
| Post Image | 1200 x 627 | |
| Cover Photo | 1584 x 396 | |
| Profile Photo | 400 x 400 | |
| Company Logo | 300 x 300 | |
| Standard Pin | 1000 x 1500 | |
| Idea Pin | 1080 x 1920 | |
| Board Cover | 600 x 600 | |
| Profile Photo | 165 x 165 | |
| Twitch | Profile Banner | 1200 x 480 |
| Offline / Video Player Banner | 1920 x 1080 | |
| Profile Photo | 256 x 256 | |
| Info Panel | 320 x 100 | |
| Emote (Large) | 112 x 112 | |
| Emote (Medium) | 56 x 56 | |
| Emote (Small) | 28 x 28 | |
| Snapchat | Snap | 1080 x 1920 |
| Geofilter | 1080 x 2340 | |
| Profile Photo | 320 x 320 | |
| Story Ad | 1080 x 1920 | |
| Threads | Profile Photo | 320 x 320 |
| Feed Image | 1080 x 1350 | |
| Feed Square | 1080 x 1080 | |
| Link Preview | 1200 x 628 | |
| Discord | Server Icon | 512 x 512 |
| Profile Avatar | 128 x 128 | |
| Server Banner | 960 x 540 | |
| Invite Splash | 1920 x 1080 | |
| Custom Emoji | 128 x 128 | |
| Sticker | 320 x 320 | |
| Role Icon | 64 x 64 | |
| Post Image | 1200 x 675 | |
| Community Banner | 1920 x 384 | |
| Avatar / Community Icon | 256 x 256 | |
| Old Reddit Thumbnail | 70 x 70 | |
| Status (Story) | 1080 x 1920 | |
| Business Catalog | 1024 x 1024 | |
| Profile Photo | 500 x 500 | |
| Group Icon | 500 x 500 | |
| Telegram | Channel Post Photo | 1280 x 1280 |
| Story | 1080 x 1920 | |
| Sticker | 512 x 512 | |
| Profile Picture | 512 x 512 | |
| Channel / Group Icon | 512 x 512 | |
| Spotify | Canvas (Looping Video) | 1080 x 1920 |
| Cover Art | 3000 x 3000 | |
| Show / Podcast Artwork | 3000 x 3000 | |
| Profile Image (Artist) | 750 x 750 | |
| Playlist Cover | 640 x 640 | |
| Substack | Newsletter Header | 1456 x 816 |
| Post / Section Hero | 1456 x 816 | |
| Publication Logo | 256 x 256 | |
| Profile Photo | 256 x 256 | |
| Medium | Story Cover | 1500 x 750 |
| Topic / Tag Header | 1500 x 750 | |
| Publication Logo (Horizontal) | 600 x 60 | |
| Publication Logo (Square) | 500 x 500 | |
| Profile Photo | 500 x 500 | |
| Bluesky | Profile Avatar | 1000 x 1000 |
| Profile Banner | 3000 x 1000 | |
| Post Image (Portrait) | 1200 x 1500 | |
| Post Image (Landscape) | 1200 x 675 | |
| Link Card Preview | 1200 x 630 | |
| Etsy | Listing Photo (Square) | 2000 x 2000 |
| Listing Photo (4:3) | 2700 x 2025 | |
| Search Thumbnail | 570 x 456 | |
| Shop Banner (Big) | 1200 x 300 | |
| Shop Banner (Large) | 3360 x 840 | |
| Shop Icon | 500 x 500 |
Frequently Asked Questions
What is the Substack header image size?
The recommended Substack header / post hero image is 1456x816 pixels (~16:9). Substack renders it at ~728x408 inside the inbox email and at the full content width on the web. Uploading at the 1456 source keeps the email version sharp on retina inboxes — uploading smaller produces visibly blurry email previews.
What size should the Substack publication logo be?
Upload the publication logo at a minimum of 256x256 pixels (1:1). It’s rendered as small as ~64x64 in the email header and slightly larger on the web. Keep the mark centered with at least 10% padding so the rounded-square or circular crop on different surfaces doesn’t clip the design.
What size is a Substack profile photo?
Author profile photos on Substack are 256x256 pixels (1:1) and are cropped to a circle on both web and email. Use a tight, well-lit headshot rather than a wide environmental portrait — the byline displays the image at ~48x48 in most surfaces.
What size should inline body images be?
Upload inline images at roughly 2x the rendered width — 1280 to 1440 pixels wide is a good source target. Substack renders body images at about 640 pixels in email and 720 pixels on the web, but the 2x upload keeps both versions sharp on retina screens.
Why are my Substack images blurry in email?
Substack auto-resizes uploaded images for the inbox version. If you upload at the rendered size (e.g., 728x408 for a header), there’s no extra resolution for retina inboxes to use, and the image looks soft. Upload from a 1456x816 (or larger) master and let Substack downscale.
What file formats does Substack support?
Substack accepts JPG, PNG, GIF, and WEBP. Use JPG for photographs and PNG or WEBP for graphics with text or sharp edges. GIFs are allowed in headers and bodies, but every frame ships inside the email payload, so heavy GIFs can push your email past Gmail’s ~102KB clipping threshold.