How to Batch Compress Images on Mac (Without Uploading Them to the Cloud)

We've all been there. You have a folder full of 5MB photos that you need to send to a client (or just save disk space). You Google "compress images", click the first result, and find yourself engaging in a risky digital ritual:

1. Upload your personal files to a server owned by who-knows-who.
2. Wait for the upload (hope your WiFi holds up).
3. Wait for the processing.
4. Download them back.

It works... mostly. But have you ever stopped to ask: Where did my photos just go?

If you're uploading product shots, maybe it's fine. But client assets? Family photos? Scans of documents?

There is a better way. Since you are on a Mac, you have a supercomputer on your desk. Why are we outsourcing a simple math problem to a server in a different continent?

The "Local-First" Advantage

Compressing files locally (on your own machine) is better for three specific reasons:

1. Privacy: Your files literally never leave your computer. You could cut your internet cable and it would still work.
2. Speed: No uploading. No downloading. Just raw processing power. The Apple Silicon chips eat image compression for breakfast.
3. Control: No "3 files per day" limits. No "Pro version required for >5MB" popups.

How to Do It (The Techy Way)

macOS actually has some built-in tools for this, if you don't mind getting your hands a little dirty.

You can use Automator to create a "Quick Action".

1. Open Automator.
2. Create a new "Quick Action".
3. Search for "Change Type of Images" or "Scale Images".
4. Save it.

It works for simple tasks, but it's clunky. You can't easily tweak quality settings, preview the results, or handle complex formats like converting HEIC to WebP while keeping the metadata.

The Professional Way: Using ShrinkPad

We built ShrinkPad because we needed a tool that was as fast as a command-line script but as easy to use as a native Mac app.

Here is the recommended workflow:

1. Drag & Drop: Grab your entire folder of images (JPG, PNG, WebP, even RAW files). Drop them onto ShrinkPad.
2. Dial it in: Adjust the quality slider. You'll see a realtime estimate of how much space you'll save.
3. Crunch: Hit the button. Done.

Stop uploading your files to the cloud.

Compress images and videos locally on your Mac. Fast, private, and no internet required.

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A Note on "Lossy" vs "Lossless"

When you are compressing, you usually have two choices:

• Lossless: Removes metadata and optimizes code stats without touching a single pixel. Good for about 10-20% reduction.
• Lossy: Smartly reduces the color palette and simplifies details that the human eye can't really see. This is where the magic happens—often reducing file sizes by 80-90% with zero visible difference.

For most web use (blogs, portfolios, email), Lossy is what you want. And doing it locally means you can aggressively test different settings without the "Upload -> Wait -> Download" loop.

Keep It Local

Your data belongs to you. The next time you need to shrink a file, skip the upload and let your Mac do the work it was designed for.

Happy compressing!