How to compress images for WhatsApp, email and websites without visible quality loss
Which format to pick, what quality setting to use, when to resize instead, and why a 4 MB phone photo can become 300 KB with no difference on screen.
A photo straight from a phone is 3–6 MB and 4000 pixels wide. A screen shows at most 1920 of those pixels, and an email or form upload often rejects anything over 1–2 MB. Compressing it well is not about a magic slider; it is three decisions in the right order.
Decision 1: how big does it need to be?
Pixel count drives file size more than anything else. Halving the width and height cuts pixels by 75% before any compression starts. Targets that work:
| Use | Max width | Typical size |
|---|---|---|
| WhatsApp / social | 1280–1600 px | 150–400 KB |
| Email attachment, forms, portals | 1200–1600 px | under 500 KB |
| Website hero image | 1600–1920 px | 200–400 KB |
| Website thumbnail / card | 600–800 px | 30–80 KB |
| Print (A4 at 300 dpi) | 3500 px | keep original |
If the image will never be printed, resize first with the image resizer or set a max width in the compressor. This step alone often does more than any quality setting.
Decision 2: which format?
- JPEG for photographs. Lossy, tiny, universally supported. Quality 75–80 is visually identical to 100 on a screen at a third of the size.
- WebP for websites. 25–35% smaller than JPEG at the same quality and supports transparency. Every modern browser reads it; some older desktop apps and email clients do not, so keep JPEG for attachments.
- PNG for screenshots, logos, text, charts and anything with transparency. Lossless by default, so photos saved as PNG are huge. A 256-colour palette PNG (what TinyPNG and the compressor on this site produce at quality below 100) shrinks graphics and even photo-like PNGs by 60–80% with no visible change.
Converting a PNG photo to JPEG or WebP with the image converter is usually the biggest single saving; converting a screenshot to JPEG, on the other hand, adds fuzzy artefacts around text.
Decision 3: what quality setting?
Start at 75 for JPEG and WebP. Compare the before/after preview at 100% zoom on a detailed area such as hair, foliage or text. Drop to 60 for social media or if you are chasing a size limit; go below 50 only for thumbnails. Above 85 the file grows quickly with almost no visible gain. For PNG, anything below 100 switches to palette compression; 100 keeps it lossless.
A worked example
A 4.8 MB, 4032×3024 photo from a phone:
- Max width 1600 → 1600×1200 pixels.
- JPEG at quality 75 → about 280 KB.
- WebP at quality 75 → about 190 KB.
That is a 95% reduction and, on a laptop or phone screen, indistinguishable from the original.
Why do it in the browser?
Most online compressors upload your image to a server, process it there and hold it for a while. The image compressor on this site decodes, resizes and re-encodes entirely in your browser: nothing is uploaded, there is no queue, and a 25 MB file works as well as a 1 MB one. Close the tab and the image is gone.
Quick checklist
Resize to the width you actually need; choose JPEG or WebP for photos and PNG for graphics; start at quality 75 and check the preview; keep the original if you might print it later.