Smush Pro (WPMU Dev) is the image optimizer embedded in the broadest WordPress ecosystem: compression, WebP conversion, lazy loading, and the Smush CDN (now assetcdn.net after the 4.3.0 migration) in one plugin that pairs with Hummingbird and the Hub for multi-site management. Its free tier is the most generous in the category – lossless smushing unlimited – while Pro adds the full stack: 2x compression, WebP conversion, CDN resizing, and directory smushing beyond the media library. Against API specialists like ShortPixel and Imagify, Smush’s differentiators are the ecosystem bundle and the free base.
Engineering discipline shows in the 4.2.x/4.3.x line: bulk smush moved to atomic operations instead of MySQL locks (reliability under load), full RTL language support, transparent-PNG detection accuracy improved, and CDN 2.0 with the domain migration – unglamorous work that keeps a widely-installed plugin dependable.
Competitive Features
- Free lossless smushing – unlimited on the free tier, unusual for the category
- Smush CDN (assetcdn.net) – edge resizing and WebP delivery (CDN 2.0, 4.3.0)
- Lazy loading – native implementation with off-screen deferral
- Directory smushing (Pro) – optimization beyond the media library
- Atomic bulk operations (4.2.0) – reliable large-library processing without MySQL locks
- Full RTL support (4.2.0) – complete right-to-left interface
- WPMU Dev ecosystem – Hub management across client sites
Key Features
- Automatic on-upload optimization – images smushed as they land
- WebP conversion (Pro) – next-gen format generation and delivery
- Image resizing – max-dimension scaling on upload
- Gutenberg block optimization – blocks with images optimized
- Incorrect-size detection – images flagged when displayed at wrong dimensions
- Accessibility option (4.3.2) – alt-text awareness
- Multisite support – network-wide optimization
Comparison with Competitors
Smush Pro vs ShortPixel
| Aspect | Smush Pro | ShortPixel |
|---|---|---|
| Free tier | Unlimited lossless | Limited credits |
| Compression levels | Lossless/lossy 2x | Smart/Glossy/Lossless |
| HEIC support | No | Yes |
| CDN | assetcdn.net included | Own CDN optional |
| Ecosystem | WPMU Dev suite | Independent |
| Billing | Membership | Credits |
Bottom line: ShortPixel’s compression quality and format support (HEIC) are the technical edge; Smush Pro’s free lossless tier and WPMU Dev bundle win on economics for WPMU Dev members. Compression ratio at aggressive settings slightly favors ShortPixel.
Smush Pro vs Imagify
| Aspect | Smush Pro | Imagify |
|---|---|---|
| Free tier | Unlimited lossless | Limited quota |
| CDN | Included (Pro) | Via WP Rocket |
| Multi-site | Hub management | Per-site |
| AVIF | No | Yes |
| Billing | Membership | Tiers |
Bottom line: Imagify generates AVIF alongside WebP – a technical edge – and pairs tightly with WP Rocket. Smush Pro counters with the free lossless base and WPMU Dev ecosystem integration. AVIF need and stack membership decide.
Recommended Stack – Smush pairs with its sibling: Hummingbird handles caching and asset optimization while Smush handles images – one Hub, complementary coverage.
Official Changelog
Version 4.3.2
Release Date: August 24, 2026
- Improvement: Accessibility option in Smush.
- Improvement: Improved transparent PNG detection accuracy.
- Improvement: Improved savings calculation in the optimization complete modal.
- Improvement: Updated Preload card description copy.
- Improvement: Security improvements.
Version 4.3.0
Release Date: August 10, 2026
- New: CDN 2.0 with multiple performance improvements and bug fixes.
- New: CDN domain migrated from smushcdn.com to assetcdn.net.
- New: Failed images list now displayed on the Directory Smush page.
- Improvement: Missing notices implemented throughout the Smush interface.
Version 4.2.0
Release Date: July 6, 2026
- New: Full RTL language support across all Smush pages, modals, and UI components.
- Improvement: Bulk smush process reliability using atomic operations instead of MySQL locks.
- Improvement: Bulk smush health checks now run via Ajax for faster stall detection.
Frequently Asked Questions
Is Smush’s free version usable?
Yes – unlimited lossless compression on the free tier is the most generous base in the category. Pro adds the meaningful upgrades: stronger compression ratios, WebP conversion, CDN, and directory smushing.
What changed with the CDN domain?
Version 4.3.0 migrated from smushcdn.com to assetcdn.net as part of CDN 2.0 – existing configurations migrate automatically, but sites with hardcoded CDN domains in custom code should update references.
Why do atomic operations matter for bulk smushing?
The 4.2.0 release replaced MySQL locks with atomic operations, meaning large-library processing no longer risks database lock contention – the failure mode that previously stalled bulk smushing on busy sites.
Does Smush convert to WebP?
Yes, with Pro – WebP generation and delivery, though not AVIF (Imagify covers both formats if AVIF is a requirement).
Can it optimize images outside the media library?
Yes – Directory Smush (Pro) processes arbitrary folders, such as theme and plugin image directories, with failed-image tracking added in 4.3.0.
Leave a Reply