Choosing the best WordPress image optimizer can dramatically improve your site speed, SEO rankings, and user experience. But with dozens of plugins available, how do you pick the right one? We tested the top contenders to help you decide.

KEY FINDING

Most image optimizer plugins only handle compression. If you also need alt text for SEO and accessibility, you'll need a second plugin—or choose an all-in-one solution like Altomatic.

Why WordPress Image Optimization Matters

Images typically account for 50-80% of a webpage's total size. Unoptimized images cause:

Slow page loads: Users abandon sites that take more than 3 seconds to load
Poor Core Web Vitals: Large images hurt your Largest Contentful Paint (LCP) scores
Lower search rankings: Google uses page speed as a ranking factor
Higher hosting costs: More bandwidth = higher bills
Bad mobile experience: Large images kill performance on cellular connections

A good WordPress image optimizer solves these problems automatically, compressing images without visible quality loss and converting to modern formats like WebP and AVIF.

What to Look for in an Image Optimizer

Before comparing plugins, understand the key features that matter:

Compression Quality

The best plugins achieve 50-80% file size reduction without noticeable quality loss. Look for "lossy" compression options for maximum savings and "lossless" for when quality is critical.

Format Conversion

Modern formats like WebP and AVIF offer 25-50% better compression than JPEG/PNG. Your optimizer should convert images automatically with fallbacks for older browsers.

Bulk Processing

If you have an existing media library, you need bulk optimization to process hundreds or thousands of images at once.

Auto-Optimization

The plugin should automatically optimize new uploads so you don't have to remember to do it manually.

Alt Text Generation

This is often overlooked, but alt text is crucial for SEO and accessibility. Most optimizers don't include this—you'll need a separate plugin unless you choose an all-in-one solution.

The Best WordPress Image Optimizers Compared

We tested the most popular plugins on a set of 50 images (mix of photos, graphics, and screenshots) to compare real-world performance.

Plugin	Avg. Compression	WebP/AVIF	AI Alt Text	Starting Price
Altomatic	72%	Yes	Yes	Free / $5/mo
ShortPixel	68%	Yes	Add-on	$4.99/mo
Imagify	65%	Yes	No	Free / $5.99/mo
EWWW	58%	Yes	No	Free / $7/mo
Smush	52%	Pro only	No	Free / $6/mo
Optimole	70%	Yes	No	Free / $19/mo

Detailed Plugin Reviews

1. Altomatic - Best All-in-One Solution

Altomatic is the only WordPress image optimizer that combines professional compression with AI-powered alt text generation in a single plugin.

Strengths:

• Up to 75% file size reduction
• AI alt text generation included (98% accuracy)
• WebP and AVIF conversion
• Bulk processing for existing libraries
• WCAG 2.1 compliant alt text for EAA/ADA compliance
• 50 free credits monthly

Limitations:

• Credit-based system (though generous free tier)
• Newer plugin (smaller user base than established competitors)

Best for: Sites that need both image optimization AND alt text without managing multiple plugins.

Pricing: Free (50 credits/mo), $5/mo (500 credits), $10/mo (1,100 credits), $20/mo (2,500 credits)

2. ShortPixel - Best for Heavy Compression

ShortPixel offers aggressive compression options and recently added an AI alt text feature as an add-on.

Strengths:

• Excellent compression algorithms
• Three compression levels (Lossy, Glossy, Lossless)
• WebP and AVIF support
• PDF compression included
• AI alt text available as add-on

Limitations:

• Alt text is separate add-on cost
• Credit system can get expensive for large sites
• Interface more complex than competitors

Best for: Users who prioritize maximum compression and don't need integrated alt text.

Pricing: $4.99/mo for 5,000 images + additional for alt text

3. Imagify - Best for WP Rocket Users

Made by the WP Rocket team, Imagify integrates seamlessly if you're already using their caching plugin.

Strengths:

• Clean, user-friendly interface
• Three compression levels
• Tight WP Rocket integration
• Automatic WebP conversion

Limitations:

• No alt text generation
• Free tier very limited (20MB/month)
• No AVIF support

Best for: WP Rocket users who want tight integration.

Pricing: Free (20MB/mo), $5.99/mo (1GB), $9.99/mo (unlimited)

4. EWWW Image Optimizer - Best for Local Processing

EWWW can optimize images on your own server without sending them to external APIs—good for privacy-conscious users.

Strengths:

• Local optimization option (no external API)
• No file size limits
• WebP conversion included
• Good for privacy requirements

Limitations:

• No alt text generation
• Local processing uses server resources
• Lower compression rates than cloud-based options

Best for: Users who can't send images to external servers.

Pricing: Free (local), $7/mo (cloud API)

5. Smush - Best Free Option (With Caveats)

Smush has the most generous free tier for basic compression, but advanced features require Pro.

Strengths:

• Generous free tier (50 images at once)
• Built-in lazy loading
• Easy to use interface
• Large user community

Limitations:

• No alt text generation
• WebP only in Pro version
• Lower compression rates
• 5MB file size limit on free

Best for: Small sites with basic optimization needs.

Pricing: Free (limited), $6/mo (Pro)

6. Optimole - Best for CDN Delivery

Optimole takes a different approach—it optimizes and serves images through its own CDN in real-time.

Strengths:

• Built-in CDN with 450+ locations
• Real-time optimization
• Automatic responsive images
• Visitor-based pricing (not image-based)

Limitations:

• No alt text generation
• Images served from external domain
• More expensive than alternatives
• Dependent on their service availability

Best for: High-traffic sites that want CDN and optimization combined.

Pricing: Free (5,000 visitors/mo), $19/mo (25,000 visitors)

The Hidden Cost: Alt Text

Here's what most comparison articles miss: image optimization is only half of image SEO.

Google uses alt text to understand images and rank them in search results. Without proper alt text:

You're invisible in Google Image Search (22% of all searches)
Screen reader users can't access your content
You may violate accessibility laws like the EAA

If you choose a compression-only plugin, you'll need a separate tool for alt text. That means:

Cost of Separate Tools:

• Image optimizer: $5-7/month
• Alt text tool (AltText.ai, etc.): $9-20/month
• Total: $14-27/month

Cost of All-in-One (Altomatic):

• Image optimization + alt text: $5-20/month
• Savings: $9-12/month

Which Plugin Should You Choose?

Choose Altomatic if:

• You need both image optimization AND alt text
• You want to simplify with one plugin instead of two
• Accessibility compliance matters (EAA, ADA, WCAG)
• You want the best value for complete image SEO

Choose ShortPixel if:

• Maximum compression is your top priority
• You already have alt text handled separately
• You need PDF optimization

Choose Imagify if:

• You're already using WP Rocket
• You prefer a simple interface
• Alt text isn't a concern

Choose EWWW if:

• You need local processing (privacy requirements)
• You can't send images to external APIs

Choose Smush if:

• You have a small site with basic needs
• Free is your only option

Choose Optimole if:

• You want optimization + CDN in one
• You have high traffic and visitor-based pricing works better

Frequently Asked Questions

Can I use multiple image optimization plugins?

No. Using multiple optimization plugins can cause conflicts, double-compression artifacts, and performance issues. Choose one and stick with it.

Will optimization affect my original images?

Most plugins keep your original images and create optimized versions. Check that your chosen plugin has a backup/restore feature before bulk processing.

How much faster will my site be?

Results vary based on your current images, but expect 40-60% faster image load times after optimization. For image-heavy sites, this can improve overall page load by 2-3 seconds.

Do I need WebP conversion?

Yes. WebP provides 25-35% smaller files than JPEG with equivalent quality. All modern browsers support WebP, and plugins handle fallbacks for the rare older browser.

Try the All-in-One Solution

Altomatic combines professional image compression with AI alt text generation—the only WordPress plugin that handles complete image SEO in one tool. Start with 50 free credits monthly.

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