Description
Make your website faster than ever with TIO’s smart optimization.
Upload your images like you’ve always done before, and we’ll handle the rest. The Image Optimizer compresses your image and converts it to a modern file format. The result is the lightest image possible, without losing the quality.
Already have a media library full of images? The new Bulk Optimize tab works through your existing uploads one at a time, with live progress, ETA, and pause/resume/stop controls — no need to leave it running in the foreground.
Why choose our plugin?
The Image Optimizer uses smart optimization parameters tuned specifically for website images. It’s designed to be a simple companion that gives you the perfect image every time. We decide on the perfect balance of size and quality for your uploaded image. TIO automatically converts your new uploads to the best format (including modern formats like WebP and AVIF), applies lossless conversion or uses lossy compression settings that don’t affect the quality.
It’s perfect for small marketing teams who don’t have the time and know-how to optimise images manually and busy agencies who can’t afford the time to do it manually at scale.
We developed TIO to solve our own frustration with image optimizers. As a result, we were able to achieve results up to 35% file size reduction compared to other compressors. Going the extra mile helps ticking off the Google PageSpeed insights image checks, especially those for next-gen image formats.
How it works?
You upload your images as you normally do — one by one or in bulk, either way is fine. You can do it via the WordPress media library and by uploading directly into your pages.
We categorise what’s in the image to apply the right optimization settings. We use suitable compression and file format conversion, as well as remove unnecessary metadata.
As an example, screenshot compression makes sure to not sacrifice text sharpness, while plain illustrations with low colour depth use more aggressive compression since it won’t affect the quality nearly as much.
We optimise the source file, so WordPress thumbnails come pre-optimised as well.
Bulk Optimize for existing media
Open Settings The Image Optimizer Bulk Optimize, hit Scan, then Start. The plugin processes one attachment per tick so your site stays responsive, shows live counts for done / savings / credits left, and gives you an ETA once it has enough data. Pause and resume any time — progress is saved server-side, so closing and reopening the tab picks up exactly where you left off.
Bulk runs preserve the original file format (JPG stays JPG, PNG stays PNG), so URLs in your posts and pages never break. Thumbnails are regenerated locally — you’re charged one credit per attachment, not one per thumbnail size. Images that can’t be optimized (too small, unsupported format, missing file, oversized, or already smaller than we can compress) are clearly labelled in the Media Library so you can see at a glance what’s been done.
Supported file formats
The only excluded file format is GIF. We support all other file formats that WordPress allows, including HEIC.
Try it for free
TIO allows you to generate one license key with 50 free image credits per website. That’s enough to test a few core pages and measure the impact.
- Get a free license key at theimageoptimizer.com/key
- Paste the key in Settings > TIO Image Optimizer
- Upload images as usual — they are compressed automatically
Credit restoration for peace of mind
Uploaded an image by mistake or we didn’t optimise it to your liking? You can reclaim the credit straight from the WordPress Media Library, subject to our Terms.
And if we notice that your image was already optimal, we won’t charge a credit in the first place — nothing to reclaim there!
External Service Disclosure
This plugin relies on The Image Optimizer API, a third-party service hosted at api.theimageoptimizer.com, to compress images. When you upload an image with auto-compress enabled, the plugin sends the image file and your site URL to this API. The API returns a compressed version of the image, which replaces the original in your media library.
No data is collected or stored beyond what is needed to process the compression request and manage your credit balance.
- Service website: theimageoptimizer.com
- Terms of Service: theimageoptimizer.com/terms
- Privacy Policy: theimageoptimizer.com/privacy
Screenshots

Settings page — connect your site with a license key 
Connected state — view credits, plan, and auto-compress toggle 
Batch upload — images are compressed automatically as they land in the media library 
Batch upload — some originals converted to WebP/AVIF for extra savings 
Illustration example — compression stats on an illustration 
Photo example — compression stats on a photo
Installation
- Upload the
nerdcow-the-image-optimizerfolder to/wp-content/plugins/ - Activate the plugin through the Plugins menu in WordPress
- Go to Settings > TIO Image Optimizer
- Get a free license key at theimageoptimizer.com/key (no account needed)
- Paste your license key and click Connect
- Upload images — they will be compressed automatically
FAQ
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Do I need an account to use this plugin?
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No. You only need a license key, which you can get for free at theimageoptimizer.com/key. No login, email, or credit card is required.
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How many free credits do I get?
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Every license key comes with 50 free credits. One credit is used per image compressed.
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What image formats are supported?
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The plugin compresses JPEG, PNG, WebP, and HEIC sources. GIF and AVIF aren’t processed — GIF because animated frames don’t survive re-compression, and AVIF because it’s already maximally compressed and re-encoding has no meaningful effect. New uploads can still be converted to modern formats like WebP or AVIF for smaller file sizes.
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Can I compress the existing images?
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Yes. Open Settings The Image Optimizer Bulk Optimize. Click Scan to count how many images in your media library still need compressing, then Start. The plugin works through your library one image at a time and regenerates thumbnails locally — one credit per image, not one per thumbnail size. You can Pause, Resume, or Stop at any point and pick up where you left off the next time you open the page. Output format is preserved (JPG stays JPG, PNG stays PNG) so URLs and post content never break.
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Do I need to keep the Bulk Optimize tab open?
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While a run is active, yes — each tick is fired by your browser. If you close the tab or navigate away, the run pauses automatically and progress is saved. Reopen the page and click Resume to continue. Scanning is more forgiving: it carries on in short server-side bursts and is safe to come back to.
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What happens if I run out of credits during a bulk run?
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The run stops cleanly and tells you exactly how many images were optimized and how much space was saved. Top up your credits and start a new run — already-optimized images are skipped automatically, so you only pay for what’s left.
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Why are some images marked as “Skipped” in the Media Library?
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The plugin won’t waste credits on images it can’t improve. Skip reasons appear next to each attachment: too small (under 10 KB), unsupported format (GIF or other), missing file (the source file is gone from the server), too large (over 100 MB), already smaller (the API determined the original is already optimal), or repeated failures (the API errored three times in a row).
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Can I undo a compression?
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No — the original file is overwritten and can’t be recovered. To get the original back, turn off auto-compress and re-upload the image. You can, however, reclaim the credit within 24 hours using the restore button in the media library or Gutenberg sidebar.
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What data is sent to the API?
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When an image is compressed, the plugin sends the image file and your site URL to
api.theimageoptimizer.com. No other data is collected. -
Will this slow down my uploads?
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Compression happens during the upload process and typically adds 1–3 seconds depending on file size. A progress indicator is shown in the media library.
Reviews
There are no reviews for this plugin.
Contributors & Developers
“TIO – The Image Optimizer – Smart Image Compression & Optimization, Built for the Web” is open source software. The following people have contributed to this plugin.
ContributorsInterested in development?
Browse the code, check out the SVN repository, or subscribe to the development log by RSS.
Changelog
1.1.1
- New: Bulk Optimize now asks you to confirm you have a backup before a run starts — “Start optimizing” stays disabled until you tick the box
- Improved: clearer help text on the Bulk Optimize screens explaining that closing the tab is safe and your progress is saved
1.1.0
- New: Bulk Optimize tab — compress existing images in your media library, one at a time, with live progress, ETA, and pause/resume/stop controls
- New: Media Library “Optimized” column now shows a “Skipped: ” pill for attachments the optimizer can’t process (too small, unsupported format, missing file, larger than 100 MB, already smaller than we can compress, or failed after retries)
- New: Settings page now has a navigation strip — your existing settings move under “Settings”, with “Bulk Optimize” as a second tab
- Preserve-format compression: bulk runs keep the original format (JPGJPG, PNGPNG) so URLs and post content never break. The existing 24-hour refund window via the per-attachment Restore button still applies.
1.0.0
- First stable release on WordPress.org
- Renamed plugin slug to
nerdcow-the-image-optimizerfor WP.org directory
0.4.0
- Renamed plugin to “TIO – The Image Optimizer by NerdCow” for WP.org compliance
- Updated all code prefixes to
nctio_/NCTIO_ - Replaced inline styles and scripts with proper wp_enqueue system
- Scoped admin notices to relevant screens only
0.3.0
- Secure site token authentication (replaces plain license key in API calls)
- Automatic migration for existing installs
- Credit restore system with 24-hour window
- Gutenberg sidebar panel with per-image compression stats
- Admin bar credits indicator
- Low credit warning notices
- AJAX-powered settings page
0.2.0
- Added auto-compress toggle
- WebP and AVIF format conversion
- Improved error handling and admin notices
- Credit balance display in settings
0.1.0
- Initial release
- Automatic image compression on upload
- License key activation
- Basic settings page
