How to Compress an Image on Mac: 6 Effective Methods

If you’re running out of storage space or need to upload a smaller image to a website or email, compressing images can help a lot. Mac users have several built-in and third-party tools to compress images easily—without compromising much on quality.

In this guide, you’ll learn how to compress an image on Mac using multiple methods, including native apps like Preview, Photos, Finder, and online tools, so you can choose the one that best suits your workflow.

Why Compress an Image on Mac?

Before diving into the methods, here are a few reasons why compressing images is important:

• Frees up disk space on your Mac
• Faster upload speeds for websites and emails
• Optimizes images for web use, SEO, and social sharing
• Maintains a balance between quality and file size

Method 1: Compress an Image on Mac Using Preview

Preview is the default image and PDF viewer on macOS, and it has a built-in feature for image compression.

Steps:

1. Open the image using Preview.
2. Click File > Export from the top menu.
3. In the dialog box:
   • Choose a different Format (e.g., JPEG if it’s PNG).
   • Adjust the Quality slider to reduce the file size.
   • Rename and choose a new location if needed.
4. Click Save.

✅ Tip: Lowering quality reduces size, but test a few levels to balance quality and file weight.

Method 2: Use Finder’s “Reduce File Size” Quick Action

macOS also includes Quick Actions in Finder to reduce file size.

Steps:

1. Right-click (or Control-click) the image in Finder.
2. Go to Quick Actions > Customize.
3. Add Reduce File Size if it’s not already listed.
4. Now go back and select Quick Actions > Reduce File Size.

🔁 Note: This creates a compressed copy automatically.

Method 3: Compress Images Using the Photos App

If your image is in the Photos app, you can export it in a compressed format.

Steps:

1. Open Photos and select the image.
2. Click File > Export > Export 1 Photo.
3. Choose the JPEG format and Low or Medium Quality.
4. Set a smaller image size from the drop-down menu.
5. Click Export, then choose a destination folder.

Method 4: Compress Images on Mac Using Online Tools

Online compressors are fast, free, and ideal if you don’t want to install anything.

Popular Online Image Compression Tools:

• TinyPNG
• ImageCompressor
• ILoveIMG

Steps:

1. Visit one of the above sites.
2. Upload your image.
3. The tool automatically compresses it.
4. Download the smaller version.

⚠️ Warning: Avoid uploading sensitive or private images to online tools.

Method 5: Use Third-Party Image Compression Apps for Mac

For bulk image compression or advanced settings, third-party apps are great.

Recommended Apps:

1. ImageOptim
   • Drag-and-drop interface
   • Free and open-source
   • Supports lossless compression
2. JPEGmini
   • Reduces file size up to 80%
   • Retains original resolution and quality
3. Squash
   • Clean UI, supports PNG, JPG, GIF
   • Great for designers and marketers
4. PhotoBulk
   • Batch compress, rename, and watermark
   • Ideal for photographers

General Steps (Using ImageOptim as Example):

1. Download and install ImageOptim.
2. Drag your images into the app.
3. It will auto-compress them using best lossless techniques.

Method 6: Compress an Image with Terminal (Advanced)

If you’re comfortable using Terminal, try this method.

Install ImageMagick (if not already installed):

brew install imagemagick

Compress image via command:

convert input.jpg -quality 75 output.jpg

Pro Tips to Keep in Mind

• Use JPEG for photos and PNG for illustrations or images with transparency.
• Keep a backup of the original image before compression.
• Always check the image quality after compression, especially for client or web use.
• For website usage, convert to WebP format for better compression and quality balance.

Final Thoughts

There are multiple ways to compress an image on a Mac—from built-in tools like Preview and Finder to powerful apps like ImageOptim or online tools. Whether you want to compress a single image or bulk-edit for a blog or portfolio, these methods have you covered.

Choose the method that suits your technical skill and need for quality preservation. Start optimizing today, and enjoy faster uploads, more storage, and smoother web performance!

FAQs: How to Compress Image on Mac