Cimo
Cimo Image Optimizer by Gambit Technologies compresses images and converts them to WebP and AVIF entirely in the browser using WebAssembly, before the file is ever sent to your WordPress server. This makes Cimo architecturally different from every other image optimizer supported by WP Media Cloud, and means the integration is completely seamless with no known limitations.
How they work together#
Because Cimo runs compression client-side in the browser before upload, the file that reaches WordPress is already the final optimized version. The upload sequence is:
- A user selects an image in the WordPress media uploader
- Cimo’s browser-side WebAssembly code compresses and optionally converts the image to WebP or AVIF in the browser
- The already-optimized file is uploaded to WordPress through the standard media upload pipeline
- WP Media Cloud offloads the file to cloud storage and serves it via CDN
WP Media Cloud offloads and serves the optimized file automatically. There is no server-side compression step, no output buffer phase, no URL rewriting by Cimo, and no local filesystem dependency. Cimo and WP Media Cloud operate on entirely separate layers with no overlap and no conflict.
Local file removal can be enabled without affecting Cimo in any way. Cimo does not check for local files at any point after upload.
Safari is not supported#
Cimo’s browser-side WebAssembly compression does not work in Safari. Users uploading images from Safari will not have their images compressed or converted by Cimo before upload. The file uploaded from Safari is the original uncompressed version, which WP Media Cloud offloads as-is.
This is a Cimo limitation, not a WP Media Cloud limitation. If your editorial team or contributors use Safari, consider pairing Cimo with a server-side optimizer such as ShortPixel or EWWW Image Optimizer to catch uploads that Cimo does not compress.
Configuration#
No configuration is required in either plugin. WP Media Cloud detects Cimo automatically and reports its status on the Integrations tab. Cimo’s free tier compresses all new uploads with no API key required. Cimo Premium adds additional conversion options and site limit increases.
Bulk optimization#
Cimo does not have a bulk optimization tool. Compression happens at the point of upload in the browser. Files uploaded before Cimo was installed, or files uploaded from Safari, are not compressed by Cimo and cannot be retroactively compressed by it. Use a server-side optimizer with a bulk optimization tool if you need to compress your existing media library.
Troubleshooting#
Images uploaded from Safari are not compressed
Safari does not support Cimo’s WebAssembly compression. This is expected. Images uploaded from Safari bypass Cimo entirely and are uploaded and offloaded as original uncompressed files.
Compression does not appear to be running
Cimo runs compression in the browser before upload. If compression is not running, confirm Cimo is active and that the browser being used is not Safari. Also confirm that JavaScript is not being blocked by a browser extension or Content Security Policy.