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ShortPixel Image Optimizer

Speed up your website and boost your SEO by compressing old & new images and PDFs. Compatible with any gallery, slider or ecommerce plugin.

What happens to the existing images, when installing the ShortPixel plugin?

Just installing the plugin won’t start the optimization process on existing images. To begin optimizing the images previously loaded on your website, you should:

  • Go to Media Library, and select which of the existing images you want to optimize.


  • Use the Bulk ShortPixel option, to automatically optimize all your previous library.

Should I pick lossy or lossless optimization?

This depends on your compression needs. Lossy has a better compression rate than lossless compression. The resulting image is not 100% identical with the original. Works well for photos taken with your camera.

With lossless compression, the shrunk image will be indistinguishable from the original, and smaller in size. Use this when you do not want to loose any of the original image's details. Works best for technical drawings, clip art and comics.

For more information about the difference read the Wiki article on the lossy/lossless difference.

Why do I need an API key?

ShortPixel Image Optimizer uses automated processes to crunch images. The ShortPixel API integrates in the dashboard of your WordPress website and processes both old and new images automatically. You can also use the same API, multiple times, in your own applications, the Documentation API shows you how.

Where do I get my API key?

To get your API key, you must Sign up to ShortPixel. You will receive your personal API key in a confirmation email to the address you provided. Use your API key to activate ShortPixel plugin in the 'Plugins' menu in WordPress.

Where do I use my API key?

You use the API key in the ShortPixel plugin Settings (don’t forget to click Save Settings). The same API key can be used on multiple websites/blogs.

How do I activate the API key on a multisite?

You have to activate the plugin in the network admin and then activate it manually on each individual site in the multisite. Once you have done that, the Settings menu appears and you can add the API key for each individual site.

As an alternative, you can edit wp-config.php and add this line define('SHORTPIXEL_API_KEY', 'APIKEY') where 'APIKEY' is the API Key received upon sign up.

If configured that way, the API key will be used for all the sites of the multisite but will only be visible on the main site's Settings page, being hidden for the rest of the sites.

How does Bulk Optimization work?

The Bulk option makes ShortPixel optimize all your images at once (not one by one). You can do this in the Media > Bulk ShortPixel section by clicking on the Compress all your images button.

The batch optimization may work slower, depending on your existing image gallery. Please be patient and do not close the WordPress admin while you are rolling the Bulk Processing on your media gallery.

Are my images safe?

Yes, privacy is guaranteed. The ShortPixel encryption process doesn't allow anyone to view your photos.

What happens with my original images after they have been processed with ShortPixel?

If you didn't make any changes in the plugin Settings and you left the 'Image backup' option checked, the originals will be located in a backup folder at:


After optimization, if you want to switch back to a certain original image, hit Restore backup in the Media Library. If you are happy with the optimized images, you can deactivate saving the backups in the plugin Settings.

What types of formats can be optimized?

For now, ShortPixel supports JPEG, PNG, PDF and GIF formats. Animated GIFs and thumbnails are also optimized. Additional formats are scheduled for optimization in the future.

Will ShortPixel work if my website is using CloudFare?

Yes, the image processing happens without interfering with the CloudFare protection. The ShortPixel and CloudFare plugins are also compatible.

I’m stuck. What do I do?

The ShortPixel team is here to help. Contact us!

Requires: 3.2.0 or higher
Compatible up to: 4.7.1
Last Updated: 3 weeks ago
Active Installs: 30,000+


4.7 out of 5 stars


14 of 14 support threads in the last two months have been marked resolved.

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