How to Compress Images Without Losing Quality
Almost everyone has hit an upload limit: an email attachment that is too large, a form that caps files at 2 MB, or a website that feels slow because its images are huge. Compression is the fix, and it does not have to mean visibly worse pictures.
This guide explains how compression works, how much you can safely remove, and how to shrink files in your browser without uploading them.
How image compression actually works
There are two broad approaches. Lossy compression reduces file size by discarding detail the eye is unlikely to notice — this is how JPG and WebP work. Lossless compression keeps every pixel and only stores the data more efficiently — this is how PNG works.
Most real-world savings come from choosing a sensible quality level. Dropping a JPG from 100% to around 80% often cuts the file size dramatically while looking identical on a normal screen.
How much quality can you safely remove?
- 85–95%: effectively indistinguishable from the original for photos.
- 75–85%: still very good for most web and email uses; the sweet spot for size vs quality.
- 60–75%: smaller files with some softening visible in fine detail; fine for thumbnails.
- Below 50%: noticeable artifacts around edges and text; only for very small previews.
Match the format to the job
The format you choose matters as much as the quality setting:
- Photos: JPG or WebP, lossy, quality around 80%.
- Screenshots and graphics with sharp edges or text: PNG, or WebP if you want smaller files.
- Images with transparency: PNG, or WebP for smaller size with alpha support.
- Modern websites: WebP usually beats JPG and PNG on size at equal quality.
Resize before you compress
The single biggest win is often resolution, not quality. A 4000-pixel-wide photo displayed at 800 pixels is wasting most of its data. Resizing to the size it will actually be shown at, then compressing, gives far smaller files than compression alone.
Compress images privately in your browser
The Image Compressor on this site lets you pick the output format and drag a quality slider, then shows how much space each file saves before you download. Nothing is uploaded, batch compression is supported, and your original is kept whenever compression would not actually help.
Try it yourself — free and private
These tools run entirely in your browser. Nothing is uploaded.
Frequently Asked Questions
What is the best quality setting for compressing images?
For photos, a quality of around 75–85% is usually the best trade-off: dramatically smaller files with no visible difference on screen.
Does compressing an image reduce its dimensions?
Not necessarily. Compression lowers file size by storing the image more efficiently; resizing separately changes the pixel dimensions. For the smallest files, do both.
Should I compress as PNG or JPG?
Use JPG or WebP for photos and WebP or PNG for screenshots, graphics and images that need transparency. WebP generally gives the smallest files.