PNG vs JPG — pick before you compress
Last week someone uploaded a 2.8MB PNG passport photo to our Compress Image to 50KB tool and wondered why the output looked soft. The format was half the problem. PNG is brilliant for screenshots; it is a heavy choice for a face photo that a portal will accept as JPG anyway.
If you need a decision in ten seconds:
| Your image | Start here |
|---|---|
| Phone camera photo for a form | JPG — convert with PNG to JPG if needed |
| Logo or icon with no background | PNG |
| Screenshot with small UI text | PNG |
| Blog hero photo on your own site | JPG or JPG to WebP |
| Signature scan on white paper | JPG at 20KB or PNG if the portal says so |
Everything below explains why those rows exist.
Two compression philosophies
PNG (Portable Network Graphics) stores image data with lossless compression. Nothing is thrown away to save space. That is why a screenshot of a banking portal — white background, black text, blue buttons — stays crisp. It is also why a casual photo saved as PNG can balloon past 3MB while looking identical to a 600KB JPG on your laptop screen.
JPG (JPEG) is built for continuous-tone images: skin, sky, fabric, grass. It removes detail the eye rarely catches, which shrinks file size fast. Push JPG too hard and you get blocky patches around text and edges. That matters on exam forms where invigilators zoom into your face.
Neither format is "better." They solve different jobs.
Transparency — the line JPG cannot cross
PNG supports an alpha channel: pixels can be fully or partly transparent. Place a PNG logo on a coloured header and the background shows through cleanly.
JPG does not support transparency. Convert a transparent PNG to JPG and empty areas become a flat colour — often white. I see rejected uploads where a candidate kept PNG for the logo field but the portal wanted JPG; the white box around the graphic looked like a paste error in the preview.
If transparency is the point, stay on PNG or test PNG to WebP for web delivery when the CMS accepts it.
File size on real uploads
Numbers vary by resolution and content, but the pattern repeats on our server logs:
| Source | Typical PNG | Same image as JPG |
|---|---|---|
| 1080×1080 selfie, plain wall | 1.2–2.5 MB | 180–450 KB |
| Full-screen Android screenshot | 800 KB–1.5 MB | 250–600 KB (text may soften) |
| Flat two-colour logo | 15–80 KB PNG | Often larger or similar as JPG — PNG wins |
Large files slow mobile uploads on Jio and Airtel during form rush hour. A student on hostel Wi‑Fi does not need a lossless photo archive; they need a file under the printed KB cap that still shows their eyes clearly.
When PNG is too heavy and the form accepts JPG, run PNG to JPG, preview the face or document text, then hit Compress Image to 100KB or 50KB as the instruction requires.
India form context — read the field label
Government and exam portals are picky about format words, not theoretical best practice.
- Photo field says JPG/JPEG: export JPG even if your phone saved PNG. PNG to JPG → size tool.
- Signature field says PNG: keep PNG; crop tight around the ink line before compressing.
- Dimension plus KB limits: both must pass. A 40KB JPG that is 4000×3000 pixels can still fail.
WEBP is excellent on modern websites but many Indian upload dialogs still grey it out. Compatibility beats clever format choice on deadline night.
Website and blog images
For pages you control — product shots, tutorial screenshots, hero banners — mix formats:
- Photographs: JPG or WebP after JPG to WebP. Smaller bytes help mobile LCP without changing what visitors see.
- UI captures and diagrams: PNG when text must stay razor-sharp; test WebP if your theme serves it with a JPG fallback.
- Icons and logos: PNG or SVG; avoid JPG unless the asset is purely photographic.
Page speed rewards right-sized files, not blindly picking one extension. Resize to the display width before format conversion. A 4000px-wide JPG converted to WebP is still heavier than it needs to be.
Common mistakes I see in support logs
Saving every export as PNG "for quality." Quality does not increase; file size does.
Converting logos to JPG for a smaller badge. You lose transparency and gain a white rectangle.
Compressing PNG repeatedly hoping to hit 20KB. Switch to JPG for photographic signatures, or crop until the ink fills the frame.
Using WhatsApp-forwarded files. Chat apps recompress. Start from the camera roll original, then convert and compress once.
Tool paths that match the format choice
- Photo too large, JPG accepted: PNG to JPG → Custom Image Compressor
- Need PNG from a JPG export for an editor: JPG to PNG — note this does not restore lost detail
- Web delivery after JPG export: JPG to WebP
- Portal rejects WebP: WebP to JPG
- Multiple scans in one upload: Image to PDF then Compress PDF
Bottom line
PNG protects edges and transparency. JPG keeps photos small enough for forms, email, and fast pages. Read the upload instruction first, then pick the format that matches the field — not the one that won a generic comparison chart.