Image, PDF, upscale, and cutout engines

Image Optimizer does not send pictures to the cloud to process them. It calls engines installed on your computer. Without the image engine, Optimize stays disabled. PDF, upscale, and cutout can be added later.

Getting started · PDF compression · Upscale and cutout

Four engines

Engine	Required?	Job
Image engine	Yes	Compress, convert, extra sizes, watermark, target size
PDF engine	Only for PDFs	Shrink PDFs by preset, keep text when possible
Upscale engine	Only when upscale is on	2× / 4× enlarge
Cutout engine	Only when cutout is on	Remove the background

Windows website installs and the Microsoft Store edition both bundle the image engine, so compression usually works out of the box. macOS can install it in one click on onboarding. PDF and vision engines are not inside the installer by default, so the download stays small. Exception: the Windows Store package includes the cutout program; the model can still download in Settings.

Check status, change paths, or download under Settings · Plugins. That download stores programs and models on this machine. It does not upload your pictures. License activation sends a salted device id only.

What is different in the Microsoft Store edition?

The Store edition cannot download an unsigned upscale engine from the network. Compress, convert, cutout, and PDF still work. For 2×/4× upscale, use the website installer , or point to an engine already on this PC. Store updates come from Microsoft Store. In-app update is off.

Typical setups

Compress and WebP only: image engine is enough.
Also PDFs: add the PDF engine.
Also cutout or enlarge: enable the switch in the plan, then download the vision engine. For Store-edition upscale limits, see the section above. If the machine cannot run it, only those rows fail.
Restore defaults does not delete downloaded engine files, but it may clear custom paths. Point to the engine again if needed.

See the privacy policy for the full list of what leaves the device.