Comparing CPU Usage of Popular WordPress Image Optimization Plugins

When optimizing images on a WordPress site, it's not just about compression efficiency or output quality, it's also about resource consumption. For websites hosted on smaller servers or shared hosting environments, CPU usage can make or break the performance during image optimization processes. Recently, I ran a series of tests to evaluate how much CPU each popular image optimization plugin consumes during peak activity on a server with a single CPU core. Here are the results: 1. EWWW Image Optimizer Peak CPU Usage: 85% EWWW Image Optimizer stood out as the most resource-intensive plugin, peaking at an 85% CPU load. While its feature set is extensive, the heavy CPU usage could cause significant slowdowns on smaller servers during optimization tasks. 2. Robin Image Optimizer Peak CPU Usage: 48% Robin Image Optimizer consumed a significant amount of CPU, reaching a peak of 48%. It strikes a balance between efficiency and resource consumption, though it might still impact performance on lightweight setups. 3. reSmush.it Peak CPU Usage: 37% reSmush.it proved to be relatively resource-friendly, with a peak CPU usage of 37%. This makes it a viable free option for those needing a lightweight plugin without compromising too much on optimization quality. 4. Imagify Peak CPU Usage: 12-13% Imagify delivered an impressive balance of CPU efficiency and image optimization, peaking between 12% and 13% CPU usage. This plugin’s low resource demand makes it a good choice for resource-constrained websites. 5. ShortPixel Peak CPU Usage: 10% ShortPixel came out on top in this test, with a peak CPU usage of only 10%. Its efficiency makes it a great choice for smaller servers and shared hosting, delivering powerful optimization while keeping resource usage low. Key Takeaways EWWW Image Optimizer: Feature-rich but resource-heavy. Robin Image Optimizer: Moderate CPU usage but could still cause slowdowns. reSmush.it: A good middle-ground option with reasonable CPU usage. Imagify: Light on resources, delivering good performance and optimization. ShortPixel: The most resource-efficient, perfect for smaller setups. So, if you use WordPress, and if CPU usage is a critical factor for your hosting environment, ShortPixel Image Optimizer is clearly the top choice. With its peak usage at only 10%, it ensures your server stays responsive while delivering high-quality image optimization. For developers and site owners looking to optimize both images and performance, these results can serve as a guide for choosing the right plugin for their needs.

Mar 26, 2025 - 09:13

Comparing CPU Usage of Popular WordPress Image Optimization Plugins

When optimizing images on a WordPress site, it's not just about compression efficiency or output quality, it's also about resource consumption. For websites hosted on smaller servers or shared hosting environments, CPU usage can make or break the performance during image optimization processes.

Recently, I ran a series of tests to evaluate how much CPU each popular image optimization plugin consumes during peak activity on a server with a single CPU core. Here are the results:

1. EWWW Image Optimizer

Peak CPU Usage: 85%

EWWW Image Optimizer stood out as the most resource-intensive plugin, peaking at an 85% CPU load. While its feature set is extensive, the heavy CPU usage could cause significant slowdowns on smaller servers during optimization tasks.

2. Robin Image Optimizer

Peak CPU Usage: 48%

Robin Image Optimizer consumed a significant amount of CPU, reaching a peak of 48%. It strikes a balance between efficiency and resource consumption, though it might still impact performance on lightweight setups.

3. reSmush.it

Peak CPU Usage: 37%

reSmush.it proved to be relatively resource-friendly, with a peak CPU usage of 37%. This makes it a viable free option for those needing a lightweight plugin without compromising too much on optimization quality.

4. Imagify

Peak CPU Usage: 12-13%

Imagify delivered an impressive balance of CPU efficiency and image optimization, peaking between 12% and 13% CPU usage. This plugin’s low resource demand makes it a good choice for resource-constrained websites.

5. ShortPixel

Peak CPU Usage: 10%

ShortPixel came out on top in this test, with a peak CPU usage of only 10%. Its efficiency makes it a great choice for smaller servers and shared hosting, delivering powerful optimization while keeping resource usage low.

Key Takeaways

EWWW Image Optimizer: Feature-rich but resource-heavy.
Robin Image Optimizer: Moderate CPU usage but could still cause slowdowns.
reSmush.it: A good middle-ground option with reasonable CPU usage.
Imagify: Light on resources, delivering good performance and optimization.
ShortPixel: The most resource-efficient, perfect for smaller setups.

So, if you use WordPress, and if CPU usage is a critical factor for your hosting environment, ShortPixel Image Optimizer is clearly the top choice. With its peak usage at only 10%, it ensures your server stays responsive while delivering high-quality image optimization.

For developers and site owners looking to optimize both images and performance, these results can serve as a guide for choosing the right plugin for their needs.