There is no best format, only a best format for a given picture. The deciding factor is almost always whether the image has hard edges or soft ones.
What is the actual difference between them?
All three are compressed image formats, but they compress on completely different assumptions, which is why each is excellent at one thing and poor at another.
JPEG is lossy and tuned for photographs. It discards high-frequency detail the eye is bad at perceiving, which works extremely well on gradients, skin, foliage and skies. It has no transparency.
PNG is lossless and tuned for flat colour. It looks for runs of identical pixels, so a screenshot with large blocks of one colour compresses enormously, while a photograph barely compresses at all. It supports full alpha transparency.
WebP does both, in two modes — a lossy mode that generally beats JPEG at the same visual quality, and a lossless mode that generally beats PNG. It supports transparency in both modes, which JPEG cannot do at all.
The practical consequence: putting a photograph in PNG makes a needlessly huge file, and putting a screenshot in JPEG makes a visibly damaged one. Those two mistakes account for most of the wasted bytes on the web.
Which one for which image?
| Image | Best choice | Why |
|---|---|---|
| Photograph | WebP, or JPG for compatibility | Lossy compression is nearly free on soft detail |
| Screenshot with text | PNG or lossless WebP | JPEG halos around type are very visible |
| Logo or icon | SVG if you have it, else PNG | Flat colour and hard edges; needs transparency |
| Illustration, line art, diagram | PNG or lossless WebP | Large flat areas compress extremely well |
| Image needing transparency | PNG or WebP | JPEG has no alpha channel at all |
| Photo for print | TIFF or high-quality JPG | Printers want maximum data, not small files |
| Email attachment | JPG | Universally readable by every client |
Where an image is genuinely mixed — a product photo with a text overlay, say — treat it as a photograph and use a higher quality setting than usual. Quality 0.85 keeps the type clean enough that nobody notices.
Is WebP safe to use yet?
On the web, yes. Every current browser supports it, and has for years — the compatibility argument that used to be decisive no longer is.
Outside the browser is a different story, and it is where WebP still causes friction. Plenty of desktop software, printers, older phones and content management systems will not open a .webp file. If somebody is going to download the image and use it elsewhere, that matters.
- Images displayed on your own site → WebP, comfortably. Typically 25–35% smaller than JPEG at the same visual quality.
- Images people will download and reuse → JPG or PNG. Do not make your reader convert a file.
- Email attachments → JPG or PNG. Some clients still will not preview WebP.
- Anything going to a printer or a print shop → not WebP. Send a high-quality JPG or TIFF.
If you have WebP files you cannot open somewhere, the Image Converter turns them back into JPG or PNG on your device.
How much does the choice actually save?
Enough to be worth thirty seconds of thought, and not enough to agonise over.
For a typical 2000-pixel-wide photograph: PNG around 4 MB, JPEG at quality 0.8 around 400 KB, WebP at equivalent quality around 280 KB. The PNG-versus-JPEG gap there is a factor of ten — that is the mistake worth avoiding.
For a typical screenshot of a settings page: PNG around 180 KB, JPEG at quality 0.8 around 250 KB and visibly worse. Here PNG is both smaller and better, which surprises people who assume JPEG is always the compact option.
The lesson in those two numbers is that there is no ranking. Format choice follows content, and content is easy to classify: soft and photographic, or hard-edged and flat.
What about quality settings and re-saving?
For lossy formats the quality slider matters as much as the format. Between 0.75 and 0.85 you get most of the compression with no visible cost. Below 0.6, blocking appears in flat areas; above 0.9 you pay for bytes nobody can see.
The more serious trap is repeated re-saving. Each lossy save discards a little more, and the damage accumulates — open a JPEG, crop it, save, reopen, adjust, save again, and you have compressed it three times. It is not visible at once, and it is not recoverable.
Keep an original in a lossless format and export copies from it, rather than editing the exported copy repeatedly. When you do need to change something, going back to the source costs nothing and preserves everything.
Frequently asked questions
Is WebP better than JPG?
For images displayed on a website, generally yes — around 25-35% smaller at the same visual quality, plus transparency support that JPEG lacks entirely. For images people download and open in other software, JPG is still the safer choice because compatibility outside the browser is patchy.
Why does my screenshot look bad as a JPG?
JPEG compression is designed for photographs and handles hard edges poorly. Text and interface elements are nothing but hard edges, so you get faint halos and ringing around every letter. Use PNG or lossless WebP for screenshots.
Does converting PNG to JPG reduce quality?
Yes, because JPEG is lossy — but on a photograph the loss is invisible at quality 0.8 and the file is roughly ten times smaller. On a screenshot or line art it is very visible and not worth it. It also discards transparency, filling those areas with solid colour.
Which format supports transparency?
PNG and WebP. GIF supports a crude single-colour transparency with hard edges. JPEG has no alpha channel at all, so any transparent area becomes solid black or white when you convert to it.
What quality setting should I use for JPEG?
0.75 to 0.85 covers almost every case. That range gives most of the file size saving with no difference anyone notices. Below 0.6 you start seeing blocking in flat areas such as skies; above 0.9 the extra bytes buy nothing visible.
Should I use HEIC from my iPhone?
Not for sharing. HEIC is efficient and fine on the device, but support elsewhere is inconsistent and many sites and Windows applications reject it. Convert to JPG before uploading or emailing, which is a lossy step but a one-time one.