How to compress an image without losing quality
“Without losing quality” means two different things. Both are possible.
In short
Truly lossless compression keeps every pixel identical: converting a PNG to lossless WebP usually saves a good share of the size. Lossy compression discards detail you cannot see: a JPEG or WebP at quality 80 to 85 is usually indistinguishable from the original at normal viewing size. Reducing pixel dimensions saves the most of all.
Key takeaways
- Lossless: identical pixels, moderate saving (PNG → lossless WebP).
- Visually lossless: quality 80–85, large saving.
- Never recompress the same JPEG repeatedly.
Lossless compression
The file gets smaller, the image stays bit for bit the same. PNG is already lossless, but lossless WebP usually stores the same pixels in less space. Removing metadata also saves a little, without touching the image.
Visually lossless compression
JPEG and lossy WebP drop fine detail the eye barely perceives. At quality 80 to 85, the difference is invisible on a phone or computer screen for most photos; below 60, blocks and halos start to appear around edges.
The biggest saving: fewer pixels
Halving the width and height divides the number of pixels by four, and the size roughly as much. If a photo is shown at 1,200 pixels wide, storing it at 4,000 is wasted space.
Original
full width and height
Half the width and height
a quarter of the pixels
What to avoid
- Re-saving a JPEG again and again: each pass loses a little more.
- Saving a photo as PNG: it becomes several times heavier with no visible gain.
- Compressing screenshots with text as JPEG: letters get blurry halos; PNG or WebP suit them better.
Image compressor
Shrink a photo to fit a size limit, and see the exact result before you download it.
Open the tool