ShortPixel vs Smush

ShortPixel Image Optimizer and Smush both compress WordPress media through a cloud service rather than crunching every pixel on your own server, but they meter that service in very different ways: ShortPixel sells image-compression credits and applies its full feature set even on the free plan, while Smush gives away compression for free but gates specific capabilities — WebP/AVIF conversion, its CDN, full-size compression — behind a Smush Pro upgrade.

Both plugins upload images to a remote API that runs proprietary optimization passes and returns a smaller file, so neither is a purely on-server tool, despite Smush's reputation as an all-in-one WPMU DEV plugin. ShortPixel's free tier still includes next-gen format conversion and PDF compression, just capped by a monthly credit allowance, whereas Smush's free tier compresses only the resized versions of an image by default and skips anything over 5MB until Smush Pro is added. Some site owners run both — Smush for lazy load and dashboard features, ShortPixel for the actual compression — though that's redundant once credits run out.

Quick verdict: Choose ShortPixel if you want WebP/AVIF conversion and PDF compression available even on a free-tier quota, and you don't mind a credit-based limit. Choose Smush if you're already inside the WPMU DEV ecosystem and want compression bundled with lazy load and directory-wide optimization, but plan to budget for Smush Pro once you need full-size compression, format conversion, or a CDN.

ShortPixel vs Smush at a glance

The install counts, ratings, and momentum figures above are StatWP's own estimates, built from WordPress.org's bucketed reporting rather than a precise published figure, and they refresh automatically instead of representing a one-time snapshot.

Feature and starting price at a glance

Because ShortPixel meters by image credit while Smush meters by feature, a low-traffic site with a modest image library will likely hit ShortPixel's monthly cap first, while a site with many large, uncompressed photos will run into Smush's free-tier file-size and bulk limits sooner.

What does ShortPixel actually do?

Per ShortPixel's own site, the plugin centers on sending images to its API for repeated, proprietary compression passes rather than a single conversion step. Its stated feature set includes:

• “SmartCompress” processing that runs an image through multiple optimization passes to find, in ShortPixel's words, “the perfect, smallest possible image.”

• Conversion to next-gen WebP and AVIF formats while keeping JPEG/PNG originals available.

• PDF compression, alongside standard image optimization.

• Bulk optimization of an entire Media Library, processed in the background without needing a browser tab left open.

• HEIC file support with automatic conversion, plus CDN delivery of scaled images through ShortPixel's companion Adaptive Images plugin.

Taken together, these features position ShortPixel as a compression-first service that also happens to handle format conversion and PDFs.

What does Smush actually do?

According to Smush's WordPress.org listing (WPMU DEV's own product page was not reachable during this research), the plugin bundles compression with a handful of site-performance extras. Its stated feature set includes:

• One-click bulk compression, optimizing images and enabling lazy load automatically.

• Lazy loading so images only load “when needed” as a visitor scrolls.

• Directory Smush, which optimizes images living outside the Media Library.

• Automatic image resizing meant to resolve PageSpeed Insights warnings (a Smush Pro feature).

• WebP/AVIF conversion and an image CDN described as running across “119 global CDN servers” (both gated to Smush Pro).

On the free tier, Smush skips images over 5MB and compresses only the resized copies WordPress generates by default, so much of that feature list depends on upgrading to Smush Pro.

What features does each one have that the other doesn't?

ShortPixel offers PDF compression and native HEIC-to-web conversion, neither of which appears in Smush's feature set at any tier. It also keeps WebP/AVIF conversion available on its free plan, whereas that same conversion sits behind a paid upgrade on the competing plugin.

Smush, in turn, bundles lazy loading and Directory Smush directly into its free tier, and it plugs into WPMU DEV's broader dashboard of site tools (performance, security, and hosting add-ons) in a way ShortPixel, as a standalone compression specialist, does not attempt to match.

Which should you actually use?

If your job is squeezing the smallest possible file size out of images plus handling PDFs or HEIC uploads, ShortPixel's credit-metered but full-featured free plan is the more direct fit. If you're running a WPMU DEV stack already, or you want lazy load and directory-wide optimization bundled into one plugin without worrying about a credit counter, Smush's free tier covers the basics and Smush Pro fills the rest in as your image library grows past its file-size and bulk caps.

Frequently asked questions

What is the difference between ShortPixel and Smush?

ShortPixel compresses images through its own cloud API and meters usage with monthly image credits, keeping WebP/AVIF conversion and PDF compression available even on the free plan. Smush also compresses through a cloud API but meters usage by feature instead of credits — its free tier skips large files and only compresses resized image copies, while format conversion and CDN delivery require Smush Pro.

Is Smush better than ShortPixel?

Neither plugin is simply “better” — they solve the free-vs-paid trade-off differently. Smush may suit sites already using other WPMU DEV tools that want lazy load and directory optimization bundled in for free, while ShortPixel may suit sites that need WebP/AVIF or PDF compression without first paying for a Pro upgrade, provided their image volume fits the free credit quota.

Does ShortPixel or Smush support WebP and AVIF conversion?

ShortPixel includes WebP and AVIF conversion on its free plan, subject to its monthly credit allowance. Smush only unlocks WebP/AVIF conversion once you upgrade to Smush Pro; the free version does not include next-gen format conversion.

Is Smush actually free, or do I need Smush Pro?

The free version of Smush is functional but limited: it skips images over 5MB, caps bulk processing, and compresses only the resized versions WordPress generates rather than the full-size original by default. Format conversion, the CDN, and automatic resizing all require Smush Pro.

Can I run ShortPixel and Smush on the same site?

Technically yes, but it's rarely worth it — running two compression plugins on the same images can lead to redundant processing and wasted ShortPixel credits. It's more common to pick one for compression and, if desired, keep the other disabled or limited to a non-overlapping feature like lazy load.

Which plugin handles PDF compression?

ShortPixel supports PDF compression directly, per its own feature listing. Smush's feature set, as described on its WordPress.org listing, does not include PDF handling.

For the live, auto-updating numbers behind this comparison, see StatWP's ShortPixel page and StatWP's Smush page, or run your own side-by-side lookup with StatWP's plugin comparison tool.