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Social media editor

Posts, stories and thumbnails with a background, text, shapes and your logo. Switch the format and Magic Resize rearranges everything.

Open the editor

Free, no account. Everything stays in your browser.

What is the social media editor?

An editor for images in social media formats. The background comes from one of the Musterli generators; on top you place text, shapes, pictures and the logo from your brand kit. Every layer remembers what it is attached to (a corner, the centre or an edge), so Magic Resize fits the same design to square, portrait, story or landscape without cutting off any text.

What you can do with it

  • One design, every format

    Design once in square and switch to story, Pinterest pin or YouTube thumbnail. Text gets smaller or wraps instead of being cut off.

  • Backgrounds from the generators

    Mesh gradients, patterns, blobs or shader gradients as the background. Space gives a new variant; fine-tune it with the controls in the side panel.

  • On brand

    Colours run through the scene's colour slots. Take over your brand palette and your logo from the brand kit with one click.

  • Layers as you know them

    Move, scale, rotate, align, distribute and group. With guides, snapping and undo.

  • Full size export

    PNG or JPG at the format size, or twice as large for crisp pictures on high resolution screens.

  • Saved in your browser

    Designs go to My designs and a draft is saved as you work. Export them as a file to move them to another device.

How it works

  1. Open the editor and pick a format, for example Instagram 4:5.
  2. Choose a background and press Space until you like the variant.
  3. Add text, shapes, pictures or your logo and arrange them.
  4. Switch the format if you need another one. Magic Resize rearranges the layers.
  5. Export as PNG or JPG and save the design to My designs.
Start designing in the social media editor

Formats

The common sizes for posts, stories, cover images and thumbnails:

  • Instagram, Facebook, LinkedIn 1:11080 × 1080
  • Instagram, Facebook, LinkedIn 4:51080 × 1350
  • Instagram portrait 3:41080 × 1440
  • Story, Reel, TikTok, Shorts 9:161080 × 1920
  • Open Graph, link preview1200 × 630
  • LinkedIn post landscape1200 × 627
  • X post 16:91600 × 900
  • YouTube thumbnail1280 × 720
  • Pinterest pin 2:31000 × 1500
  • Facebook cover1702 × 630
  • X header1500 × 500
  • LinkedIn background1584 × 396
  • YouTube channel banner2560 × 1440

Nothing leaves your device

Rendering and saving happen in your browser. Uploaded pictures are checked, SVG files are sanitised, and none of it is sent to a server.

Frequently asked questions

Is the social media editor free?
Yes. Musterli is completely free and funded by donations. There is no account, no subscription and no watermark.
What does Magic Resize do?
Every layer is attached to an edge, to the centre, or stretches across. When the format changes, margins stay the same, sizes follow the short side, and text gets smaller or wraps. Nothing is cut off.
Where are my designs stored?
In your browser's storage (IndexedDB) on this device. In My designs you can export them as a file and import them again on another device.
Can I use my own pictures and my logo?
Yes. Upload pictures right in the editor; logos come from your brand kit. Both stay local and are never part of a share link.
Does the editor work on a phone?
Viewing and exporting work everywhere. For designing, a large screen is the most comfortable.