What Happens When You Convert JPG to PNG? Full Technical Breakdown

When you convert a JPG to PNG, three things change: the file gets larger, the format becomes lossless, and the image gains the capability for transparency. One thing does not change: visual quality. The PNG looks identical to the JPG source. Here is a complete breakdown of exactly what happens — and what does not happen — during the conversion.

What Happens to Visual Quality

The visual content of the image is preserved pixel-for-pixel. PNG's encoder reads each JPG pixel's RGB value and stores it exactly in the PNG file. No color adjustment, sharpening, blurring, or resampling occurs.

A pixel that was RGB(240, 180, 120) in the JPG is stored as RGB(240, 180, 120) in the PNG. Multiply that by every pixel in the image and you have a perfect copy in a different container format.

What you cannot do: recover quality that was already lost in the JPG. If the JPG had visible compression blocks or color banding, those artifacts are preserved faithfully in the PNG. The conversion records reality — it does not improve it.

What Happens to File Size (It Gets Bigger — Here Is Why)

A 500 KB JPG becomes roughly 1.5–2.5 MB as PNG. This surprises people who expect conversion to make files smaller or keep them the same size.

The reason: JPG achieves its small size by discarding information. PNG must store all the information. A JPG at 85% quality has thrown away some of the original pixel data to achieve compression. The PNG needs to store every pixel at full precision — which requires more space.

Real examples:

• 300 KB portrait JPG → 900 KB PNG (3x)
• 800 KB landscape photo JPG → 3.5 MB PNG (4.4x)
• 150 KB product photo JPG → 500 KB PNG (3.3x)
• 50 KB logo JPG → 180 KB PNG (3.6x)

This larger size is why PNG is a working/archiving format, not a delivery format for the web. Use AVIF or JPG for web delivery; keep PNG as your lossless master.

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What Happens to EXIF Metadata

JPG files can contain EXIF metadata: camera settings (ISO, aperture, shutter speed), GPS coordinates, timestamps, software used, and copyright information.

When converting to PNG:

• Most converters strip EXIF data — PNG can technically store some metadata, but the conversion process typically does not copy EXIF from JPG to PNG.
• GPS location is usually removed — this is often a privacy benefit if you were going to share the image publicly.
• Copyright info may be lost — if you need to preserve copyright metadata, use a dedicated EXIF tool to add it to the PNG after conversion.

If preserving EXIF data matters (for professional photography, copyright documentation, or geotagging), verify your specific converter's behavior. Some tools have an option to preserve or strip metadata.

What Happens to Transparency

The converted PNG gains the technical capability to store transparency (an alpha channel). But no transparency is added during conversion — the image still has whatever background was in the JPG.

Think of it like this: converting a room with concrete floors to having a trapdoor installed. The trapdoor is now possible, but it is not open yet. You still need to actively open it (remove the background).

To use the transparency capability after conversion:

• Use an AI background remover for photos with subjects (people, products, animals)
• Use a color-removal tool to remove a solid white or black background (best for logos)
• Edit manually in GIMP or Photoshop using Selection tools

After background removal, you have a true transparent PNG that can be placed over any background without a visible box.

Frequently Asked Questions

Should I convert all my JPGs to PNG?

No — only when you have a specific reason: you need to edit further without quality loss, you need transparency support, or you want a lossless archive copy. For web delivery, JPG and AVIF are better choices. For email, JPG is fine. PNG is for editing, design work, and images that need transparency.

Does converting JPG to PNG affect print quality?

Converting to PNG preserves the original pixel data and can only help, not hurt, print quality — assuming the source JPG was high resolution. The conversion itself does not add blur or artifacts. A low-resolution JPG becomes a low-resolution PNG: converting does not increase resolution.

Does the color profile change when converting JPG to PNG?

In most converters, the sRGB color profile from the JPG is preserved in the PNG. Some converters strip embedded ICC profiles, which can cause subtle color shifts if the image was originally in a non-standard color space. For critical color work, verify the output in a color-managed viewer.

Is there any reason NOT to convert a JPG to PNG?

The main reason not to convert: file size. A PNG is 2–5x larger than the equivalent JPG. If you are optimizing for web performance or have limited storage, keeping images as JPG (or converting to AVIF for web) is better. PNG is valuable for editing and transparency; JPG is better for delivery and storage efficiency.