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Free Plugin by KeyCDN v1.6.3

Optimus

Effective image compression and optimization during the upload process. Smart, automatic and reliable.

Optimus

The facts

Rating
4.2★ from 69
Active installs
30k+
Price
Free
Last updated
2 Mar 2026
Added
Oct 2012
Requires WP
4.6
Tested up to
WP 6.9.7
Requires PHP
5.6
Downloads
699,656

Our analysis

AI-assisted

Optimus is a WordPress plugin designed to automatically reduce the file size of uploaded media files, potentially achieving reductions of up to 70%. It processes images during the upload process by sending them to the Optimus server for optimization before saving the smaller versions back to the media library. The plugin maintains image quality while extracting unnecessary data, making it suitable for users looking to improve their site's performance through image optimisation.

This plugin is particularly beneficial for bloggers and website owners who want to enhance loading times without compromising image quality. It supports bulk optimisation and works with various image formats, including the new WebP format, making it a versatile tool for managing media files on WordPress sites.

Best for: This plugin suits bloggers and website owners looking to optimise images for better performance.

What it does well

  • Reduces file size of images automatically during upload
  • Maintains image quality while optimising
  • Supports bulk optimisation for existing images
  • Compatible with WooCommerce and WordPress multisite
  • No code adjustments necessary

Where it falls short

  • Free version has a maximum file size limit of 100kb
  • Some features are only available in premium versions

Verdict

Optimus provides a straightforward solution for image optimisation in WordPress, balancing file size reduction with image quality preservation. It is a practical choice for those focused on improving site performance.

From the developer

KeyCDN's own description of Optimus, lightly tidied.

WordPress Image Optimizer

Optimus reduces the file size of uploaded media files automatically. Depending on the image and format, reductions in size of up to 70% are possible. Several kilobytes can be saved per image—these savings contribute positively to the performance of the blog website. What’s most impressive about the compression technology: the quality of the images is maintained.

There are three different versions of Optimus:

  1. Optimus (Free) as base version with limitations (e.g. max of 100kb)
  2. Optimus HQ (Premium) with expanded functionality for personal projects
  3. Optimus HQ PRO (Premium) as professional solution for customer websites

More details about the features and the pricing model on optimus.io

How does it work?

During the uploading process of images to the media library, the Optimus plugin simultaneously sends the images to the Optimus server, where the incoming material is processed and sent back in optimized form. Afterwards, the Optimus plugin saves the image version with a reduced file size in the media library.

The optimization of images – including thumbnails – is conducted in the background and outside of the view of the user. The image compression gains per file are displayed by Optimus within the media library in form of a percentage value, see screenshot.

Superfluous information that is saved by image processing programs and is not even necessary for displaying the image is extracted from image files. This way, the quality of the graphics remains intact while the image size can be reduced significantly. If you wish, Optimus keeps all author, EXIF and copyright information contained within the photos — the compressional gains will be correspondingly lower.

Optimus supports the conversion of images to the new WebP image format.

It is recommended to use the WordPress Cache Enabler plugin to integrate the converted WebP images.

Features

  • Progressive JPEGs
  • Reduction of file size during the upload
  • Optimization of all preview images of a photo
  • No adjustments to code necessary
  • Optional: no removal of EXIF and IPTC metadata
  • Optional: HTTPS connection for the image transfer (Optimus HQ)
  • Optional: conversion to the WebP image format (Optimus HQ)
  • Faster load times for blog pages
  • Support for WooCommerce
  • WordPress multisite-support
  • Bulk optimization (optimize existing images)

Privacy

  • After the image optimization and transfer process, the Optimus server immediately deletes all the temporarily stored files. No files are stored!
  • The Optimus servers are located in Germany.

Tips

  • Photos should always be saved as JPEGs rather than PNGs. The PNG format works well for illustrations, JPEG on the other hand is the right choice for photographs. Another reason: the size reduction always works more quickly for JPEGs.
  • Your images have been optimized using Desktop tools such as ImageOptim (Mac) or PNGGauntlet (Win) before you upload them? Optimus has the significant benefit of also minimizing the thumbnails (=preview images) created by WordPress. After all, themes almost always integrate thumbnails rather than original images.

Read the full description on the official page →

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