Social Media Card Cropper
Crop an image to the ratio the destination actually wants - 2:1 Twitter/LinkedIn, 1.91:1 Facebook, 1.4:1 Substack, 1:1 Instagram - with a background colour for the area the crop does not fill, so the platform does not re-crop through the part that mattered. Drop, paste or pick a file; it never leaves the browser, and no third-party CDN code is loaded. Imported Claude artifact. Source: https://github.com/simonw/tools (social-media-cropper.html, Apache-2.0).
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Details
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System prompt (SKILL.md)
---
name: social-media-cropper
description: Crop an image to the exact aspect ratio each social platform wants, with a background colour for the letterboxed area.
metadata:
tags:
- artifact-import
- media
source_url: https://tools.simonwillison.net/social-media-cropper
github_repo_url: https://github.com/simonw/tools
---
# Social Media Card Cropper
An imported Claude artifact. Drop, paste or pick an image, choose the ratio the
destination actually wants - 2:1 for Twitter and LinkedIn, 1.91:1 for Facebook,
1.4:1 for Substack, 1:1 for Instagram - drag the crop box to frame it, and set a
background colour for whatever the crop does not fill.
The point is that a card cropped to the wrong ratio gets re-cropped by the
platform, usually through the middle of whatever mattered. Picking the target
shape up front means the image you see is the image that ships.
Cropping uses Cropper.js, served from this app rather than a CDN, so the page
loads no third-party code. The image is read locally and never uploaded, no
model is called, and nothing is metered.
Release files (files)
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