How to Compress Images Without Losing Quality
Practical settings for shrinking JPG, PNG and WebP files while keeping them sharp.
Compressing an image trades a little bit of visual data for a much smaller file. Done carelessly, it produces blotchy, blurry photos. Done well, most people can't tell the difference. Here's how to get it right.
Pick the right format first
Format matters more than the quality slider. JPG and WebP use lossy compression built for photos and gradients; PNG is lossless and better for screenshots, logos and flat graphics with sharp edges or text. Compressing a photo as PNG barely shrinks it — convert it to JPG or WebP first with the Image Format Converter, then compress.
Start around 75-85% quality
For photos, quality settings between 75% and 85% are usually visually identical to the original but a fraction of the size. Below 60% you'll start to see blocky artefacts around edges and in skies. The Image Compressor and Image Quality Optimizer both let you drag the quality and watch the file size update live, so you can find the lowest setting that still looks right for your image.
Resize before you compress
A smaller image is almost always a smaller file - more effective than quality tweaks alone. If you're publishing to the web, there's rarely a reason to keep a 4000px-wide photo; 1600-2000px on the long edge is plenty for most screens. Resize first with the Image Resizer, then compress.
Let a target size do the work
If you have a strict limit - an email attachment cap or an upload rule - the Image Quality Optimizer's 'Target file size' mode searches for the highest quality that still fits your limit, so you don't have to guess and re-try.
Why the same settings look different on every photo
Compression is not one-size-fits-all because photos differ. Smooth images — skies, studio product shots, soft portraits — hide compression well and can go down to 65-70% quality before most people notice. Busy images — grass, hair, crowds, gravel, high-ISO night shots — show artefacts much sooner, because the compressor has far more detail to throw away. As a rule, test your settings on the busiest, most detailed photo of the set; if that one still looks clean, the rest will too.
Mistakes that quietly ruin compressed images
The most common one is compressing an already-compressed JPG again and again. Every save discards more data, so a photo that has been edited and re-saved five times degrades even at 'high' quality — always compress from the original. The second mistake is judging quality zoomed out: artefacts hide at thumbnail size and appear at 100%. The third is compressing before resizing, which wastes effort — a smaller image needs gentler compression for the same file size.
A simple workflow that works every time
First, pick the format (photo to JPG or WebP, graphics to PNG). Second, resize to the largest size you will actually display. Third, compress at 80% and compare the result at full size, checking faces, text and skies first — that is where problems show. Fourth, if the file is still too big, lower quality in small steps or switch to a target file size instead of guessing. Keep the untouched original somewhere safe, and you can always redo the export with different settings.
Quick tips
- Compare the before/after file size shown after each run — that's your real result, not an estimate.
- Keep your original file; compression is one-way.
- For screenshots and text-heavy images, try PNG or a high WebP quality instead of low-quality JPG.
- Never compress the same JPG over and over — each save throws away more data. Always start from the original.
- Judge the result at 100% zoom, checking faces, text and skies first — that is where artefacts appear.