PNG files are often 5–20× larger than an equivalent JPG for the same image. Converting to JPG typically reduces file size by 70–90% with minimal visible quality loss — making it faster to email, upload, and share. This guide covers every free method.
When to Convert PNG → JPG (and When Not To)
✓ Good reasons to convert
- Photographs or complex scenes
- Need to reduce file size for email or web
- Image has no transparent areas
✗ Do NOT convert if
- Image has a transparent background (logos, cutouts)
- Contains sharp text or line art
- It’s your master/archive copy
Method 1: AllMediaTools Image Converter (Free, Online)
- Open AllMediaTools Image Converter.
- Upload your PNG file.
- Select JPG / JPEG as output format.
- Set quality to 80 (recommended default for web use).
- Click Convert and download.
A PNG screenshot at 2MB typically converts to a JPG at 80–200KB at quality 80 — an 80–93% reduction.
Method 2: Windows Paint (No Install)
Right-click the PNG → Open with → Paint → File → Save As → JPEG picture. Fast for single files, no quality control.
Method 3: Mac Preview (Built-In)
Open in Preview → File → Export → Format: JPEG → adjust Quality slider (80–85 for web) → Save. Preview shows estimated file size as you adjust.
JPG Quality Settings Guide
| Quality | File size | Visual quality | Best for |
|---|---|---|---|
| 85–90 | Medium | Excellent | Professional delivery |
| 75–85 | Small | Very good — imperceptible loss | Websites, email, social |
| 60–75 | Very small | Minor loss at 100% zoom | Thumbnails, previews |
| Below 60 | Tiny | Visible artifacts | Avoid for most uses |
Batch Conversion (Command Line)
# ImageMagick — convert all PNGs in current folder
mogrify -format jpg -quality 85 *.png
# Python (Pillow)
from PIL import Image
import os
for f in os.listdir('.'):
if f.endswith('.png'):
Image.open(f).convert('RGB').save(f.replace('.png','.jpg'), quality=85)Frequently Asked Questions
What happens to the transparent background?
Transparent areas become solid white — JPG has no alpha channel. If you need to preserve transparency, convert to WebP lossless instead using AllMediaTools.
Why is my JPG larger than the original PNG?
Flat-color graphics and logos compress very efficiently in PNG (lossless). For these, keep PNG or convert to WebP lossless — not JPG. See: WebP vs JPEG vs PNG comparison.
Is JPG the same as JPEG?
Yes — identical format. JPG is the 3-character file extension from early Windows; JPEG is the full format name (Joint Photographic Experts Group).