ImageCrush vs ImageOptim: Which Mac Image Optimizer Should You Use?

TL;DR: ImageOptim is the best free image compressor for Mac — but it only compresses. ImageCrush handles the full pipeline: resize, crop, format conversion, compression, batch rename, watermarks, and reusable presets. Here's the short version:

	ImageOptim	ImageCrush
Price	Free	$14.99 (one-time)
Best at	JPEG/PNG compression	Full image optimization pipeline
Resize	—	✓
Crop editor	—	✓
Format conversion	—	✓ (JPEG, PNG, WebP, HEIC, AVIF)
Presets	—	✓ (sequences)
Batch rename	—	✓
Preserves originals	— (overwrites in place)	✓ (always creates new files)
CLI support	✓	—
Automation (Shortcuts)	—	—
Local processing	✓	✓

Should you use ImageCrush or ImageOptim? Use ImageOptim if you only need to make existing JPEG and PNG files smaller without changing format, dimensions, or anything else — it's free and excellent at that job. Use ImageCrush ($14.99, one-time) if you need to resize, crop, convert formats (WebP, HEIC, AVIF), compress, batch rename, or apply reusable presets — it handles the entire pipeline in one step. Both process images locally on your Mac with no uploads or cloud dependency.

What's the Difference Between ImageCrush and ImageOptim?

ImageOptim is a compression-only utility that makes existing JPEG and PNG files smaller. ImageCrush is a full image optimization pipeline that handles crop, resize, format conversion, compression, batch rename, and watermark export in a single batch operation. They solve different problems — and understanding the scope difference determines which one fits your workflow.

ImageOptim takes JPEG and PNG files, runs them through multiple open-source compression engines (MozJPEG, pngquant, Zopfli), and outputs smaller files in the same format. No resize, no format conversion, no cropping, no presets. It does one thing and does it well.

ImageCrush handles the complete pipeline: crop (20+ aspect ratios), resize (max dimension constraints), format conversion (JPEG, PNG, WebP, HEIC, AVIF), compression with adjustable quality, batch rename, and watermark export — all in a single operation. The preset system saves settings and chains them into sequences for multi-format output.

This matters because images account for roughly half the total weight of a typical web page, according to the HTTP Archive. Compression alone often isn't enough — modern workflows need resize to appropriate display dimensions, format conversion to WebP or AVIF, and consistent settings across projects.

ImageCrush lets you configure format, quality, dimensions, and presets before batch export — settings ImageOptim doesn't offer. With ImageOptim, compression starts the moment you drag files in with no way to adjust the output.

ImageOptim's only adjustable settings are buried in its preferences — a few toggles for JPEG quality and PNG optimization level. There's no way to configure output from the main interface, and no options for format, dimensions, or presets.

Feature Comparison: ImageCrush vs ImageOptim

Feature	ImageOptim	ImageCrush
Batch compression	✓	✓
Adjustable quality	Limited	✓ (0–100% slider)
Resize	—	✓ (max dimensions, exact size)
Crop editor	—	✓ (20+ aspect ratios, freeform, rule-of-thirds grid)
Format conversion	—	✓
JPEG output	✓ (same format)	✓
PNG output	✓ (same format)	✓
WebP output	—	✓
HEIC output	—	✓
AVIF output	—	✓
Presets	—	✓ (save + chain into sequences)
Batch rename	—	✓ (pattern templates)
Watermarks	—	✓ (text + logo)
Metadata stripping	✓ (automatic)	✓
Preserves originals	— (overwrites in place)	✓ (always creates new files)
Separate output folder	—	✓
CLI	✓	—
Shortcuts / Raycast	—	—
Folder monitoring	—	—
Local processing	✓	✓
Open source	✓	—
macOS requirement	macOS 10.8+	macOS 15.7+

The feature gap is clear: ImageOptim handles compression. ImageCrush handles compression plus everything that comes before and after it in a typical image workflow.

Where ImageOptim still leads: CLI support for scripting and build pipelines, open-source codebase, and compatibility with older macOS versions. If you need command-line integration or you're on macOS 14 or earlier, ImageOptim is the practical choice.

Format Support: Which Image Formats Can Each Tool Handle?

ImageOptim optimizes JPEG, PNG, GIF, and SVG files in their existing format — it cannot convert between formats. ImageCrush reads 7 input formats (including WebP, HEIC, AVIF, and TIFF) and converts to 5 output formats, making it the more capable tool for modern web workflows where format conversion to WebP alone can reduce file sizes by 25–34% compared to JPEG, according to Google's WebP study.

Format	ImageOptim (input)	ImageOptim (output)	ImageCrush (input)	ImageCrush (output)
JPEG	✓	✓ (same format)	✓	✓
PNG	✓	✓ (same format)	✓	✓
GIF	✓	✓ (same format)	✓	—
WebP	—	—	✓	✓
HEIC	—	—	✓	✓
AVIF	—	—	✓	✓
TIFF	—	—	✓	—
SVG	✓	✓ (SVGO)	—	—

Format choice has a larger impact on file size than compression engine choice. In our benchmark of 120 images across 5 formats, WebP produced files 39–74% smaller than JPEG depending on content type at 75% quality. AVIF compressed further still. Google's own testing confirms WebP provides 25–34% smaller files than JPEG at equivalent SSIM quality index. If you're serving images on the web, format conversion is often a bigger win than compression alone.

ImageOptim has one format advantage: SVG optimization via SVGO. If you work with vector graphics, that's a capability ImageCrush doesn't cover.

Workflow Comparison: How Many Steps Does Each Tool Take?

The clearest difference between ImageOptim and ImageCrush is the number of steps (and tools) needed for a typical web optimization task. The task: prepare 50 photos for a website — resize to max 1200px wide, export as WebP at 75% quality, rename with a clean pattern.

Step	ImageOptim workflow	ImageCrush workflow
Resize	Preview.app or `sips` CLI (separate tool)	Built-in — set max width 1200px
Convert to WebP	`cwebp` CLI or Squoosh (separate tool)	Built-in — select WebP output format
Compress	Drag files into ImageOptim	Built-in — set quality to 75%
Rename	Finder batch rename (separate tool)	Built-in — set rename pattern
Total tools needed	3–4 tools	1 tool
Preserves originals	No (overwrites in place)	Yes (always creates new files)
Saveable as preset	No	Yes

With ImageOptim

ImageOptim can't do this in one pass. You need additional tools:

Resize — Open images in Preview.app (or use sips in Terminal), resize each batch to 1200px
Convert to WebP — ImageOptim can't convert formats. Use cwebp CLI, Squoosh (one at a time), or another tool
Compress — Drag the converted files into ImageOptim
Rename — Use Finder's batch rename or a separate utility

Four steps, at least two tools, manual coordination between them. For 50 images, this takes meaningful time.

With ImageCrush

Drag the folder into ImageCrush. Configure: max width 1200px, WebP output, 75% quality, rename pattern blog-{original}-{n}. Click export.

One step. All 50 images process concurrently. Save the settings as a preset — next time it's just drag, select preset, export.

With ImageCrush + Presets

Once you've saved a preset, the workflow for your next batch is even faster:

Drag images in
Select your "Blog WebP 1200px" preset
Export

If you need multiple output sizes — say, a 1200px hero and a 600px thumbnail — chain two presets into a sequence. One drag, one click, both sizes exported simultaneously.

File Handling: Does ImageOptim Overwrite Your Originals?

Yes — and this is one of the most important differences between the two tools. ImageOptim compresses files in place, replacing the original file on disk. If you drag a photo from your Desktop into ImageOptim, that file is permanently modified. The original is gone. If you want to keep the source file, you have to manually copy it to another location before compressing — an extra step that's easy to forget and impossible to undo if you don't.

ImageCrush never modifies your source files. It always creates new output files, giving you two options:

Export to the same folder. ImageCrush writes new files alongside the originals with distinct filenames — your source files remain untouched.
Export to a separate output folder. Input and output assets stay completely separate — the cleanest workflow for organized projects.

This is a meaningful safety difference. With ImageOptim, an accidental drag-and-drop can permanently degrade a source asset. With ImageCrush, your originals are always preserved regardless of export settings.

Behavior	ImageOptim	ImageCrush
Modifies original file	Yes — overwrites in place	No — always creates new files
Preserves source assets	Only if you copy them first	Always
Output location	Same file, same location	Same folder (new filename) or separate output folder
Risk of losing originals	Yes — irreversible	None

Compression Quality: Which Tool Produces Smaller Files?

For JPEG-to-JPEG compression, ImageOptim has a slight edge. For overall file size reduction across a modern web workflow, ImageCrush produces smaller final output because it can convert to more efficient formats like WebP and AVIF. Here's how each tool approaches compression.

ImageOptim bundles best-in-class open-source compression engines: MozJPEG for JPEG, pngquant + Zopfli for PNG. For the specific task of squeezing bytes out of existing JPEGs and PNGs, these engines are among the best available. The app applies them automatically with sensible defaults.

ImageCrush uses Apple's native ImageIO framework for encoding. This means compression is handled by macOS itself — the same pipeline that powers Preview, Photos, and every other system-level image operation. The quality slider gives you granular control from 0 to 100%, and you can see results instantly.

For JPEG-to-JPEG compression specifically, ImageOptim's MozJPEG encoder may produce slightly smaller files at equivalent visual quality — MozJPEG is widely regarded as the best JPEG encoder available. But format conversion typically delivers far bigger savings than compression engine choice. Converting a JPEG to WebP at 75% quality cuts file size by 39–74% in our testing, consistent with Google's published finding that WebP achieves 25–34% smaller files than JPEG at equivalent perceptual quality. That's a much larger reduction than any single-format compression improvement can achieve.

Pricing: ImageCrush vs ImageOptim Cost Comparison

	ImageOptim	ImageCrush
Price	Free	$14.99
Model	Open source (donations welcome)	One-time purchase
Trial	Full app, always free	7-day free trial, full functionality
License	Unlimited	2 Mac activations

ImageOptim is free. That's a genuine advantage, not a footnote. If compression is all you need, paying for anything else is unnecessary.

ImageCrush costs $14.99 one-time — no subscription, no annual renewal. The 7-day trial has full functionality with no limits, so you can test it against your actual workflow before buying. For context: if ImageCrush saves you 15 minutes per batch by replacing a multi-tool workflow, the price pays for itself in a handful of uses.

When ImageOptim Is the Right Choice

ImageOptim is the better choice when you need fast, free, no-configuration compression on files that are already the right size and format. It's also the only option here with CLI support and SVG optimization.

You only need compression. Your images are already the right size, format, and crop. You just need them smaller. ImageOptim does this perfectly, for free.
You need CLI integration. ImageOptim's CLI works in build scripts, CI/CD pipelines, and Automator workflows. ImageCrush has no command-line interface.
You work with SVGs. ImageOptim bundles SVGO for SVG optimization. ImageCrush doesn't handle vector formats.
You're on an older Mac. ImageOptim supports macOS 10.8+. ImageCrush requires macOS 15.7 (Sequoia).
Budget is zero. ImageOptim is genuinely free with no limitations. Can't argue with that.

When ImageCrush Is the Right Choice

ImageCrush is the better choice when your workflow goes beyond compression — resize, format conversion, cropping, batch rename, or reusable presets. It replaces the multi-tool chain most people assemble around ImageOptim.

You need resize + compress in one step. No more opening Preview first or running sips in Terminal.
You need format conversion. Batch export to WebP, HEIC, or AVIF — formats ImageOptim can't produce.
You process images regularly. Presets and preset sequences eliminate repetitive configuration. Set up once, reuse forever.
You need cropping. The aspect ratio crop editor with rule-of-thirds grid handles social media crops, hero images, and thumbnails without a separate tool.
You need batch rename. Clean file naming for CMS uploads, SEO-friendly URLs, or organized asset libraries.
You want to keep your originals. ImageCrush never overwrites source files — it always creates new output. ImageOptim compresses in place, permanently replacing the original.

Can You Use ImageCrush and ImageOptim Together?

Yes — ImageCrush and ImageOptim can work together in a complementary workflow. Use ImageCrush for the pipeline steps ImageOptim can't handle (resize, crop, format conversion, presets) and then run the output through ImageOptim for a final compression pass using MozJPEG or pngquant.

That said, this two-tool approach is rarely necessary for web workflows. Modern formats like WebP and AVIF at 75% quality produce files that are already well-optimized. The marginal gains from a second compression pass on an already-optimized file are typically single-digit percentages — not worth the extra step for most projects.

Frequently Asked Questions

Is ImageCrush a replacement for ImageOptim?

It depends on your workflow. If you only need JPEG and PNG compression, ImageOptim does that job for free and you don't need to replace it. If you've been using ImageOptim for compression and then a second tool (Preview, sips, an online converter) for resize or format conversion, ImageCrush replaces both tools with a single app that handles the complete pipeline — crop, resize, convert, compress, rename — in one batch operation.

Does ImageCrush compress better than ImageOptim?

For JPEG-to-JPEG compression, ImageOptim's MozJPEG engine may produce slightly smaller files at equivalent visual quality. But compression engine choice is a minor factor compared to format selection. Converting to WebP at 75% quality reduces file size by 39–74% compared to JPEG — a savings ImageOptim can't achieve because it doesn't convert formats. For most workflows, the format conversion available in ImageCrush delivers significantly larger file size reductions than any compression-only tool.

Is ImageOptim still worth using in 2026?

Yes — for its intended purpose. ImageOptim remains functional on macOS Sequoia and still delivers excellent JPEG and PNG compression using MozJPEG, pngquant, and Zopfli. It hasn't added major features in recent years, but the core compression engines are still among the best available. The tool's limitations are scope, not quality: it can't resize, convert formats, crop, or save presets. If you need only compression, ImageOptim is still the right tool.

Can ImageOptim convert to WebP?

No. ImageOptim is a compression tool, not a format converter. It optimizes images in their existing format — making JPEGs smaller with MozJPEG and PNGs smaller with pngquant — without changing the file type. For WebP, HEIC, or AVIF conversion on Mac, you'll need a different tool. ImageCrush, Zipic, and Squash all support batch WebP output. For a single image, Squoosh offers free browser-based WebP conversion with a visual quality comparison slider.

Should I use ImageOptim or ImageCrush for web development?

For web development, ImageCrush is the more practical choice because modern web workflows require format conversion, resize, and consistent export settings — none of which ImageOptim provides. WebP is now supported by over 97% of browsers and delivers 25–34% smaller files than JPEG at equivalent quality, per Google's WebP study. Serving a 4000px image at 800px display size wastes bandwidth — resize matters as much as compression. ImageCrush handles all of this in one batch step with saveable presets. That said, ImageOptim's CLI makes it useful in build pipelines where you need automated compression as a final step — the two tools serve different parts of the development workflow.

Is there a free alternative to ImageCrush?

ImageOptim is free for compression. For format conversion, Squoosh is free but processes one image at a time. Zipic offers a free tier with 25 images per day including format conversion. For the full pipeline (resize + crop + convert + compress + presets in one batch), ImageCrush's 7-day free trial provides full functionality with no limitations. After the trial, it's a $14.99 one-time purchase. For a broader comparison of all options, see our roundup of the 8 best image optimizers for Mac.