Cimo – Free Instant Image Optimizer & WebP Converter

Description

Optimize all your images instantly and for free.

Cimo is a game-changer for media optimization. It optimizes, resizes, and converts your images instantly as you upload — even before the files are added to your Media Library.

Visit Cimo’s website to learn more about how Cimo does things.

From WordPress’ point of view, it’s as if you optimized your image BEFORE your uploaded it. Now, this is next-next-gen image optimization.

Cimo works like magic, drag your large image file, and an optimized image will automatically appear in your Media Library. This ensures your website load speed is perfectly optimized by keeping image sizes minimal, without compromising quality.

  • Unlimited usage – upload as many images as you want
  • Instant optimization – virtually no waiting time
  • No extra server load
  • No extra bandwidth
  • No external image-processing services

Note: Cimo works in all modern browsers (Chrome, Firefox, Edge, Opera). Image optimization currently doesn’t work in Safari, images would just upload as they normally would, please use any of the browsers listed.

Image Optimization options:

  • WebP quality – set the quality level for WebP conversion (1-100), defaults at 80%
  • Max image dimension – automatically resize images to a maximum dimension while preserving aspect ratio
  • WordPress automatic scaling – disable WordPress’s built-in 2560px image scaling
  • Thumbnail generation – disable all WordPress thumbnail generation to save disk space
  • Individual thumbnail sizes – selectively enable/disable specific thumbnail sizes
  • Preset configurations – one-click “Recommended” settings for optimal performance
  • Statistics dashboard – view total storage saved, compression ratio, and optimization metrics

How to use

Just upload images to your Media Manager as you normally would, then Cimo instantly optimizes the images to the next-gen format WebP on your browser during the upload process, the resulting optimized file is the one saved to your WordPress site. It’s amazing!

Why use Cimo?

  1. Completely Free & Unlimited – Image optimization and compression are completely free with no quotas, no limits, and no paywalls. Optimize as many images as you want, forever.
  2. Instant, Lightning-Fast Processing – Images are optimized instantly in your browser as you upload, with no waiting for server-side or external processing.
  3. Privacy-First – Your images never leave your device until they’re uploaded to WordPress. No third-party servers, no external processing, complete control over your media.
  4. Zero Server Load – All optimization happens in your browser, so your website and server stay fast and responsive.
  5. Smart Optimization – Advanced compression algorithms deliver the best quality-to-size ratio, with automatic WebP conversion for maximum efficiency.
  6. Future-Proof Format – Automatic WebP conversion ensures your images use the most efficient format, reducing file sizes by up to 80%.
  7. Instant Results – Experience faster uploads, smaller file sizes, and optimized images that load faster on your website.
  8. Universal Compatibility – Works seamlessly with the WordPress Block Editor, Elementor, Beaver Builder, and all major page builders.
  9. Developer Friendly – Clean, lightweight code that won’t interfere with other plugins or slow down your WordPress admin.

Features

  • Unlimited optimization – compress and optimize without quotas
  • WebP conversion – next‑gen format without external services
  • Client‑side processing – faster uploads, no server load
  • Privacy‑first – nothing sent to third‑party servers
  • Lightweight – no API keys, no background jobs, no server processing
  • Advanced settings – full control over quality, dimensions, and thumbnail generation
  • Statistics dashboard – track storage savings and optimization performance
  • Smart presets – one-click recommended or default configurations

Works with

  • The native WordPress Block Editor / Gutenberg
  • Should work with any plugin, but we made sure it works with these:
    • Popular Page Builders
      • Elementor
      • Divi (partial: dropping files is not yet supported)
      • Breakdance
      • Bricks Builder
      • Oxygen
      • Beaver Builder
      • WP Bakery
    • Popular Block Editor Builders
      • Stackable
      • Spectra
      • Kadence
      • Greenshift
      • GenerateBlocks

Since Cimo’s optimization works during the upload process, Cimo should be compatible with any plugin that uses images

What’s in Cimo Premium?

If you upgrade to Cimo Premium, you will get the following:

  • Video Optimization – automatically optimize and optionally downscale the resolution of videos as you upload them
  • Audio Optimization – auotmatically optimize audio files as you upload them
  • Low Quality Image Placeholders (LQIP) – for native image blocks, display a subtle image placeholder while waiting for images to load, then fade the loaded image in.

Visit our website to learn more

Video & Audio optimization are also performed as you upload your files, even before the files are added to your Media Library.

Technical Details

  • Client-Side Processing: All optimization happens in the user’s browser
  • Zero Server Load: No background processes or server-side optimization
  • Instant Results: No waiting for external APIs or server processing
  • Privacy-First: Images never leave the user’s device until uploaded
  • Browser Compatibility: Works in Chrome, Firefox, Edge, Opera (Safari support not currently available)

Perfect For

  • Website owners who want to reduce image file sizes without quality loss
  • Administrators who have content writers who always upload big images without converting them
  • Designers who always forget to convert images first before uploading to the site
  • Content creators who upload many images and want faster uploads
  • Developers building sites that need optimized images for better performance
  • Agencies managing multiple client sites with image optimization needs
  • Anyone wanting to convert images to WebP format automatically
  • Sites where server-side image processing isn’t available or desired
  • Users who want client-side image optimization for better privacy
  • Performance-focused websites that need instant image optimization
  • Developers who want zero server load from image processing
  • Privacy-conscious users who don’t want images sent to third-party servers

Screenshots

  • Automatic WebP conversion on image upload

Installation

  1. Upload the cimo folder to the /wp-content/plugins/ directory
  2. Activate the plugin through the ‘Plugins’ menu in WordPress
  3. That’s it! Cimo automatically optimizes images when you upload

FAQ

What makes Cimo different from other image optimizers?

Unlike server-side plugins, Cimo processes everything in your browser. No external APIs, no server processing, no waiting – just instant optimization as you upload.

How will I know if it worked?

When you upload an image into your Media Manager (let’s say a .jpg), you’ll notice that after uploading, it will be a .webp image! You will also find some additional information in the Media Manager about your uploaded image.

Does Cimo work in all browsers?

Cimo works in all modern browsers including Chrome, Firefox, Edge, and Opera. This currently does not work with Safari, please use one of the browsers mentioned. If you use Safari, the image will just upload as it normally would.

Does Cimo really have no limits?

Yes! Unlike other plugins that charge per image or have monthly quotas, Cimo’s image optimization and compression is completely unlimited and free forever.

Is my data sent to external servers?

No! Cimo processes everything locally in your browser. Your media assets never leave your device until they’re uploaded to your WordPress site, nor do they go to another server for processing.

How does Cimo’s client-side processing work?

Our browsers right now are quite powerful and already have the capabilities for converting images to different formats.

At the very core, the conversion is done via a clever use of JavaScript’s Canvas API to process your images in the browser right before they’re uploaded to WordPress.

This means faster uploads, no server load, and complete privacy.

What image formats does Cimo support?

Currently WebP conversion is fully supported.

Does Cimo work with existing images?

Currently, Cimo optimizes images during the upload process. For existing images, you can re-upload them to get the optimization benefits.

Does Cimo convert video and audio files?

Not currently, but we’re working on expanding our optimization capabilities.

Will Cimo slow down my uploads?

Actually, it speeds them up! Since images are compressed before upload, they transfer faster and take up less storage space.

How do I access the settings page?

Go to Settings > Cimo in your WordPress admin. There you can configure options such as WebP quality, set maximum image dimensions, control thumbnail generation, and view optimization statistics.

What are the recommended settings?

Click the “Recommended” button in the settings page to apply optimal settings:
– WebP Quality: 80% (best balance of quality and file size)
– Max Image Dimension: 1920px (perfect for modern web)
– Thumbnail Generation: Disabled (saves disk space)

These settings work great for most websites and provide excellent performance.

Can I see how much storage I’ve saved?

Yes! The settings page includes a statistics dashboard showing:
– Total storage saved
– Percentage reduction
– Number of media files optimized
– Original vs optimized file sizes

Reviews

November 21, 2025
I uploaded 5 images between 6 MB and 20 MB in less than 3 seconds. And the plugin works perfectly with Image Regenerate & Select Crop. All my custom image styles were cleanly applied and compressed to a minimal file size, and the whole thing is crystal clear. Thanks for your development. Fantastic work!
October 16, 2025
Fantastic plugin – great work!We’d love to give it 5+ stars, but a few key features are still missing: Image gallery conversion: It would be incredibly useful to have an option to convert images already in the media gallery (e.g., a “Convert with Cimo” button). Bulk conversion: Support for bulk image conversion, similar to what other plugins offer, would be a major plus. Compression details: When uploading via the media library, conversion is fast — great! However, we don’t see any compression details unless we upload via the post’s featured image section. It would be a valuable addition to display this info directly in the media gallery view. We also tested the plugin with our theme (Voxel) and noticed that images uploaded through various media widgets aren’t being converted. This might be due to missing hooks or compatibility gaps. Looking forward to future updates – this plugin has great potential! Best regards,Robert
September 25, 2025
Very happy to give this a well deserved Five Stars (★★★★★) as it’s as ingenious as it is simple. The final touch of perfection is that it works seamlessly with the Advanced Custom Fields (ACF) Image & Gallery field types. Big thanks to Benjamin Intal for this fine work! 🙌
September 15, 2025 1 reply
The biggest issue we face with clients is them uploading ridiculous images. 8000px wide anyone? – It would be great if this not only optimised but could resize to a maximum height/width. If that’s possible, please consider adding it to make it the perfect client friendly upload tool.
September 12, 2025 1 reply
Tried this plugin, and wow, images optimized like magic, no waiting, no server load, no bandwidth, no external services. Unlimited & free, quality intact.
Read all 8 reviews

Contributors & Developers

“Cimo – Free Instant Image Optimizer & WebP Converter” is open source software. The following people have contributed to this plugin.

Contributors

Changelog

1.2.0

  • New: Video Optimization (premium)
  • New: Audio Optimization (premium)
  • New: Low Quality Image Placeholders (premium)
  • New: Added rating notice at the right time
  • Fixed: Now intercepts media uploads when performed inside the block editor iframe

1.1.2

  • Fixed: When uploading images, the original image is also uplaoded.

1.1.1

  • Fixed: When uploading images using Safari, images will just upload as they normally would.

1.1.0

  • New: Statistics dashboard showing total storage saved, compression ratio, and media optimized
  • New: Admin settings page under Settings > Cimo
  • New: WebP quality control slider (1-100%) for custom compression levels
  • New: Maximum image dimension setting to automatically resize large uploads
  • New: WordPress automatic scaling control (disable the 2560px scaling threshold)
  • New: Granular thumbnail generation control – disable all or select specific thumbnail sizes
  • New: “Recommended” preset for one-click optimal settings

1.0.5

  • Fixed: Metadata saving fails if WP is installed in a subdirectory

1.0.4

  • New: Added partial support for Divi

1.0.3

  • Fixed: File prefixes are no longer used during the optimization process. The original file names are now retained.

1.0.2

  • Fixed: Dragging images on a blank editor or on top of other blocks now converts images
  • Fixed: Dragging images into the block editor now converts images
  • Fixed: Clicking on the Upload button on an image block directly now converts images
  • Fixed: Uploading images from Media > Library and in grid view now converts images
  • Fixed: Minor console JS error in some admin pages
  • Change: Added admin notice to let user know what to expect

1.0.1

  • Fixed: Minor string translation tweaks

1.0.0

Initial release of Cimo – bringing free, unlimited image optimization and compression to WordPress.

  • Initial release
  • Client-side image optimization
  • WebP conversion support
  • Unlimited compression
  • Privacy-first approach