How to compress images without losing quality – practical guide
Heavy images are the number-one cause of slow websites. The good news: with the right settings you'll often save 60–80% in size with no visible difference. This guide shows how.
Lossless or lossy?
Lossless compression (PNG, WebP lossless, FLIF) preserves every pixel exactly — the file just gets smarter encoding. Typical savings vs. uncompressed: 20–40%. Ideal for logos, screenshots and anywhere pixel precision matters.
Lossy compression (JPG, WebP, AVIF) drops image data the eye won't really notice. That shrinks photos drastically — 80–95% vs. uncompressed. For photos on websites, lossy is the right call.
Finding the sweet-spot quality level
For JPG and WebP, quality 75–85 is the sweet spot: hardly any visible difference, large file-size reduction. Below 60 you see artefacts; above 90 is mostly waste.
Tip: pull up before/after comparisons. Tools like Pixshift save right in the browser and report your savings in percent. Some images (text, hard edges) need higher quality; soft gradients are happy at 70.
Common mistakes that waste size
Loading images twice as large as the display: a 1920×1080 photo gallery on an 800×600 layout wastes 3× the necessary bytes. Resize before compressing, and use `srcset` for retina/HiDPI.
Wrong format: logos as JPG (mushy edges), photos as PNG (huge files). Match format to content — photo → JPG/WebP/AVIF, graphic with transparency → PNG/WebP/AVIF, vector logo → SVG.
How much can you actually save?
Real-world numbers: a 4 MB DSLR JPG drops to ~800 KB at quality 80 — a factor of 5. The same photo as WebP-80 lands at 600 KB. As AVIF-80, 450 KB. For pure graphics (logo, screenshot), 50-70% on top of OptiPNG is doable without sacrificing pixels.
Beware of false thrift: shrinking a 100 KB JPG to 50 KB barely matters (10-20 ms saved on load) and costs visible quality. Focus on the big chunks — compressing a 5 MB hero image pays off 50x more.
Compress your images today
Cut file sizes by up to 80% — in your browser, with no quality loss.
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