Benefits of Using ShortPixel Image Optimizer vs Other Online Image Optimizers for WordPress

Online image compressors are a great free and easy way to optimize your images or convert them to next-gen formats like WebP or AVIF. But for WordPress website owners, using an image optimization plugin like our famous ShortPixel Image Optimizer means smaller thumbnails and less work.

Below you’ll find a comparison of the two different approaches with their advantages and disadvantages.

ShortPixel Image Optimizer

ShortPixel Image Optimizer (SPIO) plugin is incredibly easy to use. For starters, you just need to follow this step-by-step guide to install and use ShortPixel Image Optimizer guide.

Then add an image to your Media Library and click the Optimize Now button if our plugin didn’t do it automatically (there is a setting for that).

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The next step is to add the image to any post. Note that the size Large is selected by default.

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When we publish the post and check the image size, we see that the size is 64.7 KB. Notice that the image is a thumbnail (see the -1024x576 ending in the filename) because the image size is Large.

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And we all know that in the vast majority of cases, the image that the website visitor sees is a thumbnail and not the original image, whether it is optimized or not.

Online image optimizer

Now we do the same test, but instead of using ShortPixel’s plugin, we use any free online optimizer, for example ShortPixel’s free online image compressor, and upload the image we have on our computer.

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We download the optimized image and add it to another WordPress post. Note that the Large size is again selected by default.

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Now we publish the second post and check the image size: 138 KB!

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This is the problem with WordPress and online optimizers. If you want it to work and optimize all your images, you need to upload and optimize the original image and also the thumbnails. That means you have to upload and optimize 100 images instead of the 10 images you thought (assuming you average 9 thumbnails per image).

And it’s all a manual process. That means you have to download and upload the image yourself, which is very time consuming.


Optimizing your WordPress images with the ShortPixel Image Optimizer plugin has clear advantages:

  • the resulting thumbnails become smaller (64.7 KB vs. 138 KB in our example or 53% smaller)
  • the process is faster and requires less work, as you only need to click one button.