Compress image for Substack Newsletter
Substack emails render images at 1400 px max. Uploads should target that dimension and JPEG format.
KBTarget locked for this page
WebP is typically 25–35% smaller at the same quality — useful when the target is aggressive.
Runs entirely in your browser — nothing is uploaded.
Substack newsletters are delivered by email. Email clients (particularly Outlook desktop) don't render WebP, so JPEG is the safe format. Substack accepts up to ~ 25 MB per image but chokes on very large uploads.
This preset produces a 1400 px JPEG at quality 85 — sharp on retina, ~ 350 KB per image.
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Frequently asked questions
- What size should an image be for Substack newsletter body image?
- The preset on this page reflects the recommended dimensions for Substack newsletter body image. Uploading at these dimensions avoids the auto-crop or auto-downscale that the platform would otherwise apply.
- Does the platform re-encode after upload?
- Yes — most platforms re-encode uploaded images to their internal format and bitrate. Starting from a clean, correctly sized image means only one round of lossy re-encoding rather than two.
- What format should I use for Substack newsletter body image?
- The preset uses the format recommended for Substack newsletter body image. JPEG is the safest universal choice; some workflows benefit from WebP or PNG for specific reasons (transparency, screenshots, etc.).
- Is anything uploaded?
- No. The compression and resize run in your browser. The image only leaves your device when you upload it to Substack newsletter body image yourself.
- Can I batch process multiple images for Substack newsletter body image?
- Yes — use the bulk compressor to process a folder of images with the same settings. Every image gets the correct dimensions and quality for Substack newsletter body image.
Prepare a Substack — newsletter body image image.
Drop your image — the tool applies the correct dimensions and quality for the platform.
Back to the tool