nixtool

Nix Image Optimizer helps optimize your WordPress media library by converting supported image uploads to WebP automatically and giving you tools to manage existing images, generate lightweight featured images, and improve image SEO metadata.
Features:
<ul>
<li>Automatically converts new JPG, JPEG, PNG, and AVIF uploads to WebP.</li>
<li>Bulk-compresses existing Media Library images.</li>
<li>Shows compression statistics in a Media Log.</li>
<li>Adds optional watermark support before compression.</li>
<li>Generates blog-style featured images from post title, category, author name, and avatar.</li>
<li>Supports custom featured image background colors, gradients, typography, and output dimensions.</li>
<li>Auto-fills missing image ALT text and attachment descriptions from post content.</li>
<li>Includes Basic and Advanced Image SEO Metadata modes.</li>
<li>Scans and backfills existing posts with safe generated-metadata rules.</li>
<li>Includes an unused media scanner and cleaner.</li>
<li>Works with WordPress Media Library metadata and regeneration flow.</li>
</ul>
<h3>External services</h3>
This plugin can connect to the WordPress avatar system, which commonly uses Gravatar, when the Featured Image Generator is configured to include the post author’s avatar.
When the avatar option is enabled, the plugin requests the author’s avatar URL while showing the featured-image preview in the WordPress admin and while generating a featured image for a post or page. WordPress builds that avatar URL from the author’s user account email address according to the site’s normal avatar settings. The plugin downloads the avatar image from that URL so it can draw the circular author avatar into the generated featured image. If the avatar option is disabled, or if no avatar URL is available, the plugin does not request the avatar image and uses a local placeholder shape instead.
The avatar service is provided by Gravatar/Automattic: 
Terms of Service: https://wordpress.com/tos/ 
Privacy Policy: https://automattic.com/privacy/

Nix Image Optimizer

Convert images to WebP with bulk compression, media log, watermarking, image SEO, featured image generation, and unused media cleanup.

Erdinc Bulat

Erdo Image Optimizer is a complete Image SEO & Performance Suite for WordPress. Convert images to WebP/AVIF, bulk-fix alt text, sanitize filenames, enable lazy loading, clean up unused media, and run a 6-point SEO audit — all from a single, modern dashboard.
Most image optimization plugins stop at compression. Erdo goes further: every image in your media library receives a professional SEO health score (out of 6 points). You will know exactly which images are hurting your Google rankings and how to fix them, in bulk, in minutes.
<h4>Why Erdo Image Optimizer?</h4>
<ul>
<li>Image SEO Audit (6 Points): Every image gets a score from 0 to 6 based on alt text, filename quality, title, contextual relevance, dimensions, and format. Fix failing criteria with one click — no guesswork.</li>
<li>WebP & AVIF Converter: One-click conversion from JPEG, PNG, GIF, and HEIC/HEIF to WebP or AVIF. Smart Quality mode automatically finds the smallest file size that still looks great.</li>
<li>Bulk Alt Text Generation: Automatically generate descriptive alt text from filenames for every image missing it. Fix hundreds of images in seconds — critical for accessibility and image SEO.</li>
<li>Filename Sanitizer: Transforms messy uploads like <code>IMG_1234 (copy).JPG</code> into SEO-friendly <code>professional-web-design.webp</code> at upload time. Bulk-rename existing images with automatic database reference updates.</li>
<li>Unused Media Cleanup: Scans your entire library to find images that appear nowhere on your site. Free up disk space and stop confusing search crawlers with orphaned files.</li>
<li>Lazy Loading & WebP Serving: Inject <code>loading="lazy"</code> into content images automatically. Serve WebP to compatible browsers via <code>.htaccess</code> rewrite (Apache) or PHP <code><picture></code> fallback (all servers).</li>
<li>Background Queue & WP-CLI: Bulk-convert thousands of images via WP-Cron — close the browser tab and let it run. Full CLI support: <code>wp erdo convert</code>, <code>audit</code>, <code>restore</code>, <code>stats</code>, <code>clean-cache</code>.</li>
<li>BunnyCDN & REST API: Upload converted images directly to BunnyCDN storage. Headless access via <code>/wp-json/erdo/v1/stats</code> and <code>/wp-json/erdo/v1/audit</code> REST endpoints.</li>
</ul>
<h4>Full Feature List</h4>
Compression & Conversion
<ul>
<li>One-click WebP and AVIF conversion with original backup and one-click restore</li>
<li>HEIC/HEIF (iPhone photos) conversion to WebP/AVIF via Imagick</li>
<li>Smart Quality mode — automatically finds the smallest file size that still looks great</li>
<li>Lossless mode for zero-quality-loss compression</li>
<li>Max Upload Width — automatically resize oversized images before conversion</li>
<li>EXIF metadata stripper — reduce file weight and protect photographer privacy</li>
<li>GIF, JPEG, PNG, HEIC → WebP/AVIF in one click</li>
</ul>
Image SEO & Alt Text
<ul>
<li>Image SEO Auditor with 6-point health score for every image in your library</li>
<li>Bulk Alt Text — generate alt text from filenames for all images missing it</li>
<li>Automatic filename sanitization on upload (removes spaces, special chars, uppercase)</li>
<li>Bulk rename all existing filenames with automatic database reference update</li>
<li>SEO Audit CSV export — download a full spreadsheet for reporting</li>
<li>Missing Alt Text filter — focus the dashboard on images that need fixing</li>
</ul>
Performance & Delivery
<ul>
<li>Lazy loading (<code>loading="lazy"</code>) injected into content, thumbnails, and gallery images</li>
<li>WebP serving via <code>.htaccess</code> rewrite (Apache) or PHP <code><picture></code> element rewriter</li>
<li>BunnyCDN integration — upload converted images directly to CDN storage</li>
<li>Background Queue — bulk convert via WP-Cron, browser tab can be closed</li>
</ul>
Developer & Dashboard
<ul>
<li>REST API: <code>/wp-json/erdo/v1/stats</code> and <code>/wp-json/erdo/v1/audit</code> endpoints</li>
<li>WP-CLI commands: <code>wp erdo convert</code>, <code>audit</code>, <code>restore</code>, <code>stats</code>, <code>clean-cache</code></li>
<li>Dashboard widget — key stats visible from wp-admin home</li>
<li>Before/After comparison slider — drag to compare original vs optimized</li>
<li>Right-click context menu on every image card</li>
<li>Grid size selector (Small / Medium / Large) with localStorage persistence</li>
<li>SVG upload support with automatic XSS sanitization for administrators</li>
<li>Multisite / network admin support</li>
<li>Modern, clean dashboard with format badge and SEO score on every card</li>
</ul>

Erdo Image Optimizer: Compress & Convert to WebP/AVIF (SEO Audit, Alt Text, Lazy Load)


Expected another "compress and done" plugin and got a complete image SEO toolkit instead. The standout for me is the 6-point audit score on every image. It tells you exactly which ones have weak alt text, bad filenames or the wrong format, and you fix them in bulk instead of one at a time. The WebP/AVIF conversion handles HEIC from iPhone photos too, and it keeps your originals with one-click restore, so there's basically no risk in trying it.



What sold me as a developer was the depth under the hood. Full WP-CLI support (wp erdo convert/audit/restore), real REST endpoints, a background queue so big libraries keep converting after you close the tab, and clean i18n. That's an unusual amount of care for a free plugin, and it's clearly built to WordPress standards, proper nonces, capability checks and escaping throughout.



Runs smoothly, does what it promises, and no upsell nagging. Highly recommended, and I'm looking forward to where this one goes.


More than a compressor a real image SEO suite


Not just another compressor - the 6-point SEO audit on every image and bulk alt text generation alone save hours of work. WebP/AVIF conversion with automatic original backup makes experimenting risk-free, and the WP-CLI commands and REST API endpoints show this was built by a developer for developers. Highly recommended.


Finally an image plugin that takes SEO seriously

Compress & convert images to WebP/AVIF. SEO-audit every image, bulk-fix alt text, filenames & unused media. Lazy loading & BunnyCDN.

Nix Image Optimizer vs Erdo Image Optimizer: Compress & Convert to WebP/AVIF (SEO Audit, Alt Text, Lazy Load)