JPEG vs WebP vs AVIF in WordPress: Real Benchmark Data (4 Plugins Tested)
Source: Dev.to
TL;DR
I benchmarked 4 image‑optimization plugins on the same WordPress install with the same source image, all in lossy mode. AVIF is the clear winner, delivering up to 91 % compression. The differences between plugins are larger than the marketing claims suggest. Full data tables below.
Why I Did This
I got tired of vague comparisons with no real numbers. So I set up a controlled test: same server, same WordPress install, same source image, and every major image‑optimization plugin ran through the identical benchmark. No affiliate links—just numbers.
- Source image: Single JPEG, 2400 × 1590 px (494 KB) – a real‑world photo, not a thumbnail.
- Plugins tested: ShortPixel, Imagify, Optimole, EWWW Image Optimizer.
- Method: Each plugin processed the same source file in its most aggressive lossy mode. Output files were downloaded and measured directly.
Test Setup
| Item | Details |
|---|---|
| Source JPEG | 494 KB, 2400 × 1590 px |
| Processing mode | Lossy (most aggressive setting per plugin) |
| Measurement | macOS Finder – exact byte counts |
| Resizing | None (same dimensions in, same dimensions out) |
| Formats tested | JPEG, WebP, AVIF (where available) |
| Paid add‑ons | Noted where AVIF/WebP were locked behind a paid tier |
Results
JPEG (lossy)
| Plugin | Output | Reduction | Verdict |
|---|---|---|---|
| 🏆 ShortPixel | 89 KB | 82.0 % | 🟢🟢🟢🟢🟢 |
| 🥈 Imagify | 119 KB | 75.9 % | 🟡🟡🟡🟡 |
| 🥉 Optimole | 128 KB | 74.1 % | 🟡🟡🟡 |
| EWWW (Premium) | 154 KB | 68.8 % | 🔴🔴 |
WebP (lossy)
| Plugin | Output | Reduction | Verdict |
|---|---|---|---|
| 🏆 ShortPixel | 55 KB | 88.9 % | 🟢🟢🟢🟢🟢 |
| 🥈 Imagify | 74 KB | 85.0 % | 🟡🟡🟡🟡 |
| 🥉 Optimole | 79 KB | 84.0 % | 🟡🟡🟡 |
| EWWW | 91 KB | 81.6 % | 🔴🔴 |
AVIF (lossy)
| Plugin | Output | Reduction | Verdict |
|---|---|---|---|
| 🥇 ShortPixel | 43 KB | 91.3 % | 🟢🟢🟢🟢🟢 |
| 🥈 Imagify | 69 KB | 86.0 % | 🟡🟡🟡🟡 |
| 🥉 Optimole | 133 KB | 73.1 % | 🔴🔴 |
| EWWW | — (paid add‑on) | — | ⚪ |
Key takeaway: AVIF delivers ~91 % compression versus ~82 % for JPEG. The 494 KB source photo shrinks to just 43 KB with ShortPixel’s AVIF output. Most plugins either don’t support AVIF or lock it behind a paid tier.
Plugin Impressions
- ShortPixel – Best results across all three formats and the easiest to set up. No upsells, no locked formats. Ideal for fresh installations.
- Imagify – Clean interface and decent results, but not quite at ShortPixel’s level in these tests. If you’re already using it and happy, there’s no urgent reason to switch.
- Optimole – Works more like a CDN than a traditional optimizer, which can be useful on shared hosting. Compression is fine but unremarkable, and you have less control over the process.
- EWWW Image Optimizer – The most complex to configure. AVIF is locked behind a paid upgrade, which was frustrating to discover after setup. The premium tier does unlock better compression, but ShortPixel provides comparable results out of the box.
Checklist Before Choosing a Plugin
- AVIF support – Should be available out of the box, not a paid add‑on.
- Aggressiveness of lossy mode – Verify actual file sizes; “aggressive” labels can be misleading.
- Bulk optimization – Essential if you’re migrating or switching plugins mid‑project.
- Setup time – If you need >30 minutes of documentation reading just to get started, it may be a red flag for client sites.
- Automatic serving of modern formats – The plugin should handle WebP/AVIF delivery per browser without extra configuration.
- Behavior on free‑tier limits – Some plugins silently stop optimizing once the limit is reached; know this before going live.
Final Thoughts
Take these numbers as a reference, not a verdict. The “best” plugin ultimately fits your workflow, budget, and site requirements. If you’re starting a new WordPress project in 2026, ShortPixel currently checks every box in my tests. Feel free to share what plugins you’re using in the comments.