Image Optimization Plugins: Specific Trade-offs Across Three Tools

The best image optimization plugin for your WordPress site is the one whose pricing model matches your image upload patterns. The features look comparable across Smush, ShortPixel, and EWWW Image Optimizer, but the pricing structures are different enough that the same site can pay 5x more on one plugin than another despite identical compression results.

That's a counterintuitive thing to lead with. The standard framing is "ShortPixel compresses better, Smush has the cleaner UI, EWWW is the budget option." Those characterizations are roughly accurate but they miss the cost dimension that determines which plugin actually fits a given site.

How the three plugins price differently

Smush Pro is subscription-based. $7.50/month flat, unlimited image optimization, unlimited bandwidth on the included CDN. The Smush Pro pricing scales with sites (their bundle includes other WPMU DEV plugins) but the per-site cost is roughly $90/year for a one-site license.

ShortPixel uses image credits. 500 free credits per month (effectively 500 images compressed monthly). Paid plans start at $9.99 for 30,000 one-time credits or $9.99/month for 7,000 monthly recurring credits. The credit model rewards sites with predictable image upload volumes; it punishes sites with bursty patterns (Black Friday product upload sprees, photographer portfolio dumps).

EWWW Image Optimizer has two pricing models. The "API" version uses credits like ShortPixel ($9/month for 4,000 monthly credits). The "Local Server" version runs the optimization on your hosting server and is fully free, but it requires the host to have specific image processing binaries (jpegtran, optipng, pngquant) installed and accessible, which not all shared hosts allow.

The actual compression results

A test photo (3024x3024 RAW exported from a Canon R6, 8.4MB JPEG) compressed by each tool to the "lossy" setting:

• Smush Pro lossy: 1.42MB (83% reduction)
• ShortPixel lossy: 1.31MB (84% reduction)
• EWWW Image Optimizer (API, lossy): 1.39MB (83% reduction)
• EWWW Image Optimizer (local, jpegtran -optimize): 5.8MB (31% reduction — lossless only)

The three lossy paid options produce roughly equivalent file sizes; ShortPixel is marginally better but within margin of error. The local EWWW option is dramatically worse because it can only do lossless compression without the API; that's not a fair comparison since the API tier costs money.

For a WebP conversion test on the same photo:

• Smush Pro WebP: 890KB
• ShortPixel WebP: 820KB
• EWWW WebP: 855KB

WebP conversion produces roughly 35% additional savings on top of the lossy compression across all three tools.

The confidence-band on compression quality

A 1.31MB file is the typical answer for ShortPixel's compression of a high-resolution photo. If your tool returns dramatically different numbers (say, 500KB or 2.5MB on the same input photo), one of two things has happened: you've chosen a different compression preset (Smush has "Lossless," "Lossy," and "Aggressive" tiers, with the same options in the others) or your image was different than the test (different dimensions, different content complexity affect compression dramatically).

For a content website with mostly UI graphics and screenshots, the compression savings from any of the three tools are roughly equivalent. The plugin that wins for your site is the one whose pricing structure fits the upload pattern, not the one whose algorithm produces marginally smaller files on a photo benchmark.

For a photography site, e-commerce site, or any site with substantial original photographic content, the algorithm quality matters more. ShortPixel's compression is consistently the best of the three on photographic inputs by a small margin. Smush Pro is a strong second. EWWW with the API is competitive but with fewer features around the optimization itself.

A specific tip if you're choosing between these tools today: use the free tier of each on the same five images for a week. Compare the resulting file sizes and the visual quality of the compressed outputs. The trial gives you a real-data answer for your specific images that no aggregated benchmark can match. The plugins won't try too hard to convert you during the trial; their actual business model assumes a few weeks of evaluation before commitment.