How to Compress Images on iPhone, iPad, & Mac using Medrea
Leibniz Li
@leibnizliWhat is Medrea? Medrea is a professional media toolkit for iPhone, iPad, and macOS that processes images, audio, and video completely offline. Unlike online converters that require uploading your private files to a server, Medrea runs advanced compression algorithms directly on your device, ensuring 100% privacy and security.
Download Medrea on the App Store
Why Compress Locally?
Most "free" online compressors make money by collecting data or showing ads. They also require a stable internet connection. Medrea solves this by embedding industry-standard encoders directly into the app:
- No Uploads: Your photos never leave your device.
- No Waiting: Process files instantly without queuing.
- Professional Engines: Uses the same algorithms as top tech companies (Mozilla, Google).
Supported Formats & Technologies
Medrea isn't just a basic resizing tool. It supports modern formats and advanced encoding engines:
| Format | Engine / Technology | Best Use Case |
|---|---|---|
| JPEG | MozJPEG (by Mozilla) | The gold standard for photos. Creates smaller files than standard JPEG at the same quality. |
| PNG | Zopfli (by Google) | Lossless. Best for archiving where every pixel must be perfect. Slow but efficient. |
| AVIF | AV1 | Next-gen format. Incredible compression efficiency, often 50% smaller than JPEG. |
| HEIC | Apple High Efficiency | The standard iPhone format. Great balance of size and quality. |
Step-by-Step Guide
1. Select Your Images
Open Medrea and navigate to the Image tab.
- iPhone & iPad: Tap "Add Files" or select from the Photo Library.
- macOS: Drag and drop files directly into the window, or use the file picker.
- Batch Processing: You can select dozens of images at once. Medrea handles them in a queue.
2. Choose Your Compression Strategy (Settings)
Tap the Gear Icon (Settings) to customize how Medrea processes your files. This is where Medrea shines.
For Photographers (JPEG/HEIC)
- Format: Keep as Original or convert to MozJPEG for maximum compatibility.
- Quality: 75-85% is usually the "sweet spot" where the human eye can't see the difference, but file size drops significantly.
- Resolution: Use "Original" to keep full detail, or scale down (e.g., to 1920px width) for sharing on social media.
For UI/Web Designers (PNG)
You have three powerful choices for PNGs:
- Apple Optimized: Fast, system-standard compression.
- Zopfli (Lossless): Choose this if you need bit-perfect accuracy. It takes longer (brute-force search) but finds the smallest possible lossless file.
For Animations (GIF, WebP, AVIF)
Medrea supports Animated WebP and AVIF, which are far superior to GIF.
- Preserve Animation: Toggle this ON to keep the motion. Toggle OFF to extract just the first frame as a static image.
- Note: Re-encoding animations can be CPU intensive.
3. Review and Start
Tap Start.
- Smart Check: Medrea compares the compressed result with the original. If the compressed file ends up larger (which can happen with already optimized files), Medrea discards it and keeps the original to ensure you never waste space.
- Before/After: You'll see exactly how much space you saved (e.g., "-2.5 MB").
Troubleshooting / FAQ
Q: Why did Medrea keep the original file? A: This happens if the compressed version is larger than the original. This often occurs if you try to compress a file that is already highly optimized (like an image from WhatsApp or Discord) with high-quality settings.
Q: Which format is best for the web? A: WebP is widely supported and efficient. AVIF is even smaller but slightly less compatible on older browsers. Both are better than JPEG.
Q: Does it remove metadata? A: Yes, compression often strips bulky metadata (like thumbnails and some EXIF data) to save space, which also helps with privacy.
Ready to reclaim your storage? Download Medrea today.