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HostSalt Image Optimizer connects your WordPress site to the HostSalt IO cloud API to automatically compress and convert images on upload. No server-side libraries required — just install, connect and start saving bandwidth.
Features:
<ul>
<li>Automatic optimization on upload — no manual steps needed</li>
<li>Converts images to WebP or AVIF for maximum compression</li>
<li>Smart format selection — picks whichever format saves more</li>
<li>Lossless backup — restore originals any time with one click</li>
<li>Bulk optimize your entire existing media library</li>
<li>Bulk restore all images to their originals</li>
<li>Monthly usage dashboard built into wp-admin</li>
<li>Works with all themes and page builders</li>
<li>Multisite compatible</li>
</ul>
How it works:
When you upload an image, HostSalt Image Optimizer sends it securely to the HostSalt IO API. The API compresses and converts the image, then returns the optimized version. The original is kept as a backup so you can restore at any time.
A free plan is available with 50 optimizations per month. Paid plans are available for higher volumes.
<h3>External Services</h3>
This plugin sends image data to an external API service operated by HostSalt:
<ul>
<li>API endpoints: https://images.hostsalt.com/optimize and https://images.hostsalt.com/usage/{site_id}</li>
<li>Data sent: image file contents, output format preference, quality setting, max width setting, and a unique site identifier derived from your site URL (MD5 hash)</li>
<li>Data received: optimized image file</li>
<li>When: on image upload (automatic), on manual Optimize button click, and during bulk optimization</li>
</ul>
This service is operated by HostSalt. Please review the following before use:
<ul>
<li>Terms of Service: https://hostsalt.com/terms-of-service/</li>
<li>Privacy Policy: https://hostsalt.com/privacy-policy/</li>
</ul>
No personal user data is transmitted. Only image files and site configuration are sent.

HostSalt Image Optimizer

Automatically optimize, compress and convert images to WebP or AVIF on upload — powered by the HostSalt IO API.

Freemius

Harv

Harvify Image Optimizer helps WordPress administrators convert Media Library images to modern WebP and AVIF formats without running heavy compression work inside PHP.
The plugin scans lightweight attachment metadata first, then your browser converts selected images in a small queue. Images are processed with Web Workers and OffscreenCanvas where available, uploaded back through authenticated WordPress REST API requests, and released from browser memory as each item finishes.
This client-side approach is designed for shared hosting environments where PHP memory limits and execution timeouts can interrupt large image optimization jobs.
<h4>Key features</h4>
<ul>
<li>Convert JPEG, PNG, WebP, and AVIF source images to WebP or AVIF.</li>
<li>Scan one source format at a time so existing target-format images are not accidentally reprocessed.</li>
<li>Select a few images for a test run before processing the full queue.</li>
<li>Skip small files, very large images, selected upload paths, or filename patterns.</li>
<li>Deliver Pro sidecar variants through PHP picture tags when available.</li>
<li>Adjust quality and queue concurrency from the admin screen.</li>
<li>Save queue state in the browser with IndexedDB so work can resume after interruption.</li>
<li>Keep wp-admin responsive by doing conversion work in browser workers.</li>
<li>Process images locally in your browser without using an external optimization API.</li>
<li>Optional original-file deletion, disabled by default.</li>
</ul>
<h4>Privacy and external services</h4>
Harvify Image Optimizer does not send images to a third-party compression service, load scripts from external CDNs, or track usage. Images are fetched by your browser from your own WordPress site and uploaded back to your own WordPress REST API.
AVIF encoding uses bundled WebAssembly encoder files. The current AVIF path uses the Apache-2.0 licensed @jsquash/avif single-thread encoder, with the earlier bundled wasm-avif encoder retained as a local fallback.
<h4>Format testing</h4>
If you want to experiment with AVIF conversion outside your WordPress Media Library first, you can use this browser-based test tool:
<a href="https://conversores.online/en/avif-to-png-converter/" rel="nofollow ugc">AVIF to PNG Converter</a>

Harvify Image Optimizer for WebP and AVIF

Convert Media Library images to WebP or AVIF locally in your browser.

HostSalt Image Optimizer vs Harvify Image Optimizer for WebP and AVIF