How to Convert JPG to PNG — "You Can't Un-Lose Quality" Explained

Converting JPG to PNG is one of the most common image conversion requests — and also one of the most misunderstood. Many people do it hoping to "improve" a blurry or artifact-filled JPG. It does not work that way. JPG compression is lossy and irreversible — the pixel data that was discarded when the JPG was saved is gone forever. Converting to PNG creates a lossless container, but that container holds a lossy image. You get a larger file with the same quality.

That said, there are completely legitimate reasons to convert JPG to PNG. This guide explains the technical reality clearly, then covers every case where the conversion is genuinely useful, and shows you how to do it for free.

The Hard Truth: JPG to PNG Does Not Restore Quality

When a JPG is saved, the encoder performs Discrete Cosine Transform (DCT) compression. It divides the image into 8×8 pixel blocks and discards high-frequency detail (fine texture, sharp edges) according to the quality setting. This discarded data is gone permanently — not stored anywhere, not recoverable.

When you convert that JPG to PNG, the process is:

1. The JPG is decoded back to raw pixels. These pixels already have the compression artifacts from lossy encoding: subtle blurring, color banding, "ringing" around sharp edges, and 8×8 block-boundary patterns visible at high compression.
2. Those pixels — artifacts and all — are written to a PNG file using lossless DEFLATE compression.
3. The result: a PNG file that is larger than the source JPG, contains the same artifacts, and has no improvement in visual quality.

When JPG to PNG Is Still the Right Move

Despite the quality caveat, there are four legitimate reasons to convert JPG to PNG:

File Size: Expect a Significant Increase

The size increase is dramatic because JPG achieves small file sizes by discarding data — PNG must store the full pixel data losslessly, which is inherently larger. This is not a bug or a conversion error; it is the correct behavior.

Method 1: Convertlo — Free, Browser-Based

Method 2: GIMP — Free, Open Source

Method 3: ImageMagick CLI — Batch Conversion

# Convert single JPG to PNG
convert input.jpg output.png

# Batch: convert all JPGs in folder to PNG
mogrify -format png *.jpg

# With PNG compression level (0=fastest, 9=smallest)
convert input.jpg -define png:compression-level=6 output.png

# Python: bulk convert using Pillow
from PIL import Image
import glob
for f in glob.glob("*.jpg"):
    Image.open(f).save(f.replace(".jpg", ".png"), "PNG")

Adding Transparency After Converting JPG to PNG

The number one reason people convert JPG to PNG is to enable background removal — something JPG cannot do because it has no alpha channel. Once you have a PNG, you can add transparency:

• Convertlo Remove BG tool: convertlo.pro/remove-bg.html — AI-powered background removal, runs in browser. Drop the original JPG directly (it handles the conversion internally).
• Photoshop: Open the PNG, use Select → Subject or the Magic Wand tool to select the background, then press Delete to make it transparent.
• GIMP: Image → Flatten Image first, then Image → Flatten Image (to ensure alpha channel), then use Fuzzy Select to remove background areas.
• Canva: Upload the PNG, click the image, click Edit photo → Background Remover (Pro feature).

Note: if the background and foreground have similar colors, automatic tools may struggle. Manual masking in Photoshop or GIMP gives the best results for complex images.

Frequently Asked Questions