Image Optimizer

Περιγραφή Image Optimizer allow to use free Image optimization based on API. provides image size reduction based on several advanced algorithms. The API accept JPG, PNG and GIF files up to 5MB.

This plugin includes a bulk operation to optimize all your pictures in 2 clicks ! Change your image optimization level to fit your needs !
This service is used by more than 300,000 websites on different CMS (WordPress, Drupal, Joomla, Magento, Prestashop…).

The plugin includes an option to exclude some pictures of the optimizer.

Since Aug. 2016, allows to optimize pictures up to 5MB, for free !

This plugin has initially been developped by Maecia Agency, Paris.


  • The simple interface


  1. Upload resmushit-image-optimizer to the /wp-content/plugins/ directory.
  2. Activate the plugin through the ‘Plugins’ menu in WordPress.
  3. All your new pictures will be automatically optimized !

Συχνές Ερωτήσεις

How great is ?

Since we’ve optimized more than 4,000,000,000 pictures, we’ve risen new skills. Our service is still in development to bring you new crazy functionalities.

Is there an «Optimize on upload» feature ?

Absolutely, this feature is enabled for all new pictures to be added, and can be disabled on will.

Can I choose an optimisation level ?

Yes, by default the optimization level is set at 92. But you can optimize more your pictures by reducing this optimization level.

Can I go back to my original pictures ?

Yes, by excluding/reverting this asset you’ll have your original image available.

Is it possible to exclude some pictures from the optimizer ?

Yes, since version 0.12, you can easily exclude an asset from the optimizer.

Have I a risk to lose my existing pictures ?

Nope ! Image Optimizer creates a copy of the original pictures, and will perform optimizations only on copies.

Is it free ?

Yes ! Absolutely free, the only restriction is to send images below 5MB.


Great for reducing size of my images!

The only caveat is that there is no option to delete the original images. If this was possible I would have rated this 5 stars! This is a feature coming I hear and cross my fingers it will get here soon!

Works just fine

Optimization rate is as promised comparing to results I usually have on desktop with jpegoptim and optipng. Optimizing hundreds of images in a bulk is surely a pain (cause it's slow), but that's something to expect from free service. The issue I reported on support forum was resolved in a timely manner. So, works just fine.

1300+ Images in Gallery and Upload becomes horrible

We maintain a blog with over 1300 images in gallery, out of the sudden upload times became tragic. We read elsewhere that another similar plugin is causing the issue, soooo we deactivated and guess what! Good job but in our case is deleted, considering that our budget is between free and almost free 🙂 Have a good one!

When several image added in bulk fail

Great plugin but not designed to use in big site with a lot of images... 1. Problem, appear 504 error (ajax fail in console) when you go to options (as i can see in source code plugin just take ALL images... and if you hacve 80k of this.... there is a poblem) Possible solution: may be add pagination on this page? 2. We use theme witch add images in bulk to the gallery, so when you add 20 at once, the plugin fail, because i believe the optimizing process iss very hard Possible solution: Reduce optimizing process to one image, do another only if one is done? I hope it will be fixed and i will change ratiing for this great plugin. Thank you.

Ummm not good results

So I manually optimized several photos today via Photoshop with the typical great results and thought I'd give these image plugins a try...after reading some comparison reviews it became apparent this is one of top picks so, I'll give it a try. I resized some images to 1200x900 manually, enabled this plugin, and proceeded to upload some of the images. The images were resized upon upload to 1024x768 as expected which IS a smaller image mind you...I also left the compression at the default 92% (and yes optimize on upload is enabled). I then checked the "optimized images" and found that despite the image sizes being decreased which in theory should also shrink the file size, they actually INCREASED in file size by an average of 10% and some closer to 20%... How can you say this thing works if it makes a SMALLER image a larger file size lol. I also tested by uploading images at 1024x768 so they would not be resized on upload... After uploading and "optimizing", it once again enlarged their file sizes quite a bit. My current image went from 72KB to 90KB after "optimizing". This app literally does nothing (at least on upload) and when it does, it makes them BIGGER despite losing 8% quality. I then disabled this plugin and uploaded the same images without any of the file sizes becoming larger or changing at all as expected...undeniable proof. Don't just read what it says about reducing sizes people, check for yourselves like I did... I did then manually optimize the entire uploads folder and checked the file sizes, the zip was smaller afterwards but I did not compare any individual images yet but still, the "optimize on upload" is NOT a good thing to do as it hurts not helps!

Lots of problems

This would be a great plugin if it worked out... There is : - Errors when uploading PDF or DOC files - Errors when some characters are presents in the filename (like "©") - Weird design in media library I've deleted this plugin from hundreds of website...sorry.
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Συνεισφέροντες & Προγραμματιστές

“ Image Optimizer” είναι λογισμικό ανοιχτού κώδικα. Οι παρακάτω έχουν συνεισφέρει στη δημιουργία του.


Σύνοψη αλλαγών


  • Fix on attachment metadata incorrectly returned (will fix issues with other media libraries)


  • WordPress 5.0 compatibility


  • Fix PHP errors with PHP 7.2
  • Code refacto


  • Fix JS on «Optimize» button for a single picture
  • Provide a new «Force Optimization» for a single picture


  • Avoid filesize () : stat failed errors if a picture file is missing
  • Log check file permissions
  • Check extensions on upload (avoid using API if it’s not a picture)
  • Increase API Timeout for big pictures (10 secs)


  • Fix bug (non-working optimization) on bulk upload when «Optimize on upload» isn’t selected
  • New header banner for 4 billionth images optimized


  • Add correction for allow_url_fopen support
  • News feed loaded from a SSL URL


  • Log rotate if file too big


  • Tested up to WordPress 4.9.5
  • New contributor (resmushit)
  • Translation completion


  • Tested up to WordPress 4.9.1
  • New header banner for 3 billionth images optimized 🙂


  • Tested up to WordPress 4.8.1


  • New header banner for 2 billionth images optimized 🙂


  • Slovak translation fix


  • Slovak translation fix


  • Italian translation added (thanks to Cristian R.)
  • Description minor correction


  • Slovak translation added (thanks to Martin S.)


  • Bug fix when images uploaded > 5MB
  • List of files above 5MB
  • Translation minor corrections


  • Error management if webservice not reachable
  • Filesize limitation increased from 2MB to 5MB


  • CSS Fixes


  • Translation correction
  • News feed images correction


  • Delete also original file when deleting an attachment
  • Exclusion of an attachment of the optimization (checkboxes)
  • Adding french translation
  • Code optimizations
  • 4.6.x check
  • Minor bugs corrections


  • Optimize on upload
  • Statistics
  • Log services
  • Interface rebuild
  • News feed from


  • plugin base
  • bulk optimizer