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Quick answer
To reduce an image's file size, open Zappy Compress Image, add a JPG, PNG or WebP, choose Normal (about 20% smaller), Medium (about 50%) or Extreme (about 80%) and click Compress image. The dimensions stay the same and the smaller file downloads straight away. Nothing is uploaded.
How to reduce image file size in 3 steps
Add your image
Open Compress Image and drop in a JPG, PNG or WebP up to 25 MB.
Pick a level
Normal barely changes how it looks, Medium is right for email and websites, and Extreme gives the smallest file for strict upload forms.
Compress and download
Click Compress image. You'll see the before and after sizes, and the smaller file downloads.
Compress or resize: two ways to make an image smaller
There are two levers, and they work best together:
- Compress keeps the same width and height but stores the picture more efficiently. Good when the dimensions must stay the same.
- Resize reduces the number of pixels. A 4000-pixel phone photo shown on a website at 1200 pixels can lose about 90% of its weight with no visible change.
Which format gives the smallest file?
Swipe to compare →
| Format | Best for | File size |
|---|---|---|
| JPG | Photos | Small, and adjustable with compression |
| PNG | Screenshots, logos, text, transparency | Larger for photos, sharp edges |
| WebP | Websites | Often 25–35% smaller than JPG at similar quality |
Saving a photo as PNG can make it several times bigger than a JPG. Convert website images with WebP converter for the smallest files.
How to reduce photo size on iPhone
iPhone photos are often 2–5 MB each. When you email a photo from the Photos app, Mail may offer Small, Medium or Large sizes. For any other use, open Compress Image in Safari and choose the photo from your library. It even works in Airplane Mode once the page has loaded.
How to reduce image file size on a Mac or Windows PC
Mac: in Preview, choose File > Export, set the format to JPEG and move the Quality slider left. Watch the file size shown in the dialog.
Windows: Paint can resize (Resize > Pixels) and re-save as JPG, but it doesn't let you choose the compression level. Compress Image in your browser gives you three levels and shows the result before you download.
Common size limits to aim for
- Email: keep photos under 1–2 MB each so several fit in one message.
- Websites: 100–300 KB per large image keeps pages fast.
- Upload forms: check the limit. Many ask for 100KB, 200KB or 500KB.
Frequently asked questions
How do I reduce an image file size for free?
Open Zappy Compress Image, add your photo, choose Normal, Medium or Extreme and click Compress image. The smaller file downloads straight away.
How do I reduce image size without losing quality?
Use the Normal or Medium level. Normal cuts about 20 percent with no visible change, and Medium about 50 percent with barely any.
What is the difference between compressing and resizing?
Compressing keeps the dimensions and stores the image more efficiently. Resizing reduces the number of pixels. Doing both gives the smallest file.
How do I compress a photo on iPhone?
Open Compress Image in Safari, choose the photo from your library and pick a level. It runs on the phone, so nothing is uploaded.
Which image format is smallest?
For photos, WebP is usually smallest, then JPG. PNG is much larger for photos but best for screenshots and logos.
Is my image uploaded?
No. Compress Image works inside your browser, so the photo never leaves your device.