Smaller files. Better quality.
Local processing plus an optional cloud pipeline for advanced codecs and resolution-aware compression. Available formats and speed depend on server capabilities, quota, source image, and settings.
Measured February 16, 2026 using 3 Unsplash JPEGs (2400px wide) (2766 KB total) in lossy (maximum quality) mode. These are test results, not guaranteed savings.
Two processing modes
Local optimization uses available server libraries. Optional cloud optimization supplies advanced codecs and processing when the plan, quota, and service are available.
Local
Runs on your server using PHP GD or Imagick. Handles basic JPEG/PNG compression, lazy loading, and dimension attributes.
- JPEG/PNG compression via server libraries
- Lazy loading with native loading="lazy"
- Missing width/height attributes added
- WebP conversion if server supports it
Cloud
Images are sent to our dedicated optimizer running Sharp 0.35, cjpegli, and cjxl binaries. BullMQ queue with Redis handles concurrency.
- cjpegli for JPEG (Google's encoder)
- Sharp for WebP and AVIF
- cjxl binary for JPEG XL
- Smart compression based on resolution
- Background queue with WP-Cron polling
Four format engines
Each format uses a different compression engine optimized for that codec.
JPEG (cjpegli)
79.4% savingsPerceptual JPEG encoding through cjpegli, with a Sharp JPEG fallback when the dedicated encoder is unavailable.
WebP
84.3% savingsThe modern standard for web images. 20-30% smaller than JPEG at equivalent quality. Auto-served to browsers that support it via <picture> tags.
AVIF
91.7% savingsAV1-based image format with dramatic compression gains. We use effort level 4 (not 9) to keep encoding under 5 seconds per image while maintaining quality.
JPEG XL
55.9% savingsOptional next-generation output encoded through a compatible cjxl binary. Browser delivery support varies, so standard fallbacks remain essential.
Quality adapts to resolution
Large images tolerate more compression without visible quality loss. Smart compression exploits this automatically.
| Resolution | Quality Offset | Floor |
|---|---|---|
| > 8 MP | -25 quality | min q45 |
| > 4 MP | -20 quality | min q50 |
| > 2 MP | -15 quality | min q55 |
| > 1 MP | -10 quality | min q60 |
| < 1 MP | No offset | User quality |
Format-specific offsets
| Format | Offset | Floor |
|---|---|---|
| AVIF | -30 from base | min q35 |
| WebP | -25 from base | min q35 |
| JPEG (cjpegli) | -20 from base | min q35 |
Example: A 2400px hero image (3.84 MP) at user quality 75 with AVIF output: base 75 - 15 (resolution) - 30 (AVIF offset) = q30, floored to min q35.
WebP savings vs competitors
Measured on the same 3 test images at each plugin's maximum lossy setting. Results vary by source image and quality configuration.
Try the image engine
Local compression, lazy loading, cloud cjpegli, AVIF, JXL, and smart compression — all built into one plugin.