PNG vs JPEG Metadata: What's the Difference?

PNG and JPEG are the two most common image formats on the web, but they store metadata in fundamentally different ways. Understanding these differences matters for privacy, file size, and compatibility.

How JPEG Stores Metadata

JPEG files store metadata in APP markers — special segments at the beginning of the file, before the actual image data.

APP1 — EXIF Data

The most important marker. Contains:

• Camera make and model
• Shooting settings (aperture, shutter speed, ISO)
• GPS coordinates
• Timestamps
• Orientation
• Thumbnail image

EXIF data follows the TIFF format structure internally, which is why it can contain so many different fields.

APP2 — ICC Profile

Embeds the color profile (usually sRGB) for accurate color reproduction across different displays.

APP0 — JFIF Header

Basic file information like resolution and aspect ratio. Present in most JPEG files.

APP13 — IPTC Data

Used by news agencies and stock photo services. Contains:

• Caption and headline
• Keywords and categories
• Copyright and credit
• Location (city, country)

COM — Comments

Freeform text comments. Sometimes contains software info or copyright notices.

XMP (in APP1)

Adobe's Extensible Metadata Platform. Can contain editing history, keywords, ratings, and more. Stored as XML text.

How PNG Stores Metadata

PNG uses a chunk-based structure. The entire file is a series of chunks, each with a 4-letter type code. Metadata lives in ancillary (non-essential) chunks.

tEXt, iTXt, zTXt — Text Data

Key-value pairs of text. Common keys:

• Title, Author, Description
• Software, Source, Comment
• Creation Time

The iTXt variant supports Unicode. The zTXt variant uses compression.

eXIf — EXIF Data

Added to the PNG specification in 2017. Contains the same EXIF data as JPEG files (camera info, GPS, timestamps). Not all PNG files have this — it's mainly found in PNG files converted from photos.

iCCP — ICC Profile

Same purpose as in JPEG — embeds a color profile for accurate color display.

tIME — Timestamp

Records the last modification date and time in UTC.

pHYs — Physical Dimensions

Specifies pixels-per-unit, defining the intended physical size (DPI/PPI) of the image.

gAMA, cHRM, sRGB — Color Info

Gamma correction, chromaticity coordinates, and sRGB rendering intent. These affect how colors are displayed.

Side-by-Side Comparison

Feature	JPEG	PNG
EXIF support	Native (APP1)	Via eXIf chunk (since 2017)
GPS data	Common	Rare (only converted photos)
ICC profiles	APP2 marker	iCCP chunk
Text metadata	COM marker only	Rich text chunks (tEXt, iTXt)
IPTC data	Supported (APP13)	Not supported
XMP data	Supported (APP1)	Via iTXt chunk
Timestamps	In EXIF	tIME chunk + EXIF
Compression	Lossy (DCT)	Lossless (Deflate)
Transparency	No	Yes (alpha channel)

Which Format Has More Metadata?

JPEG files typically contain far more metadata than PNG files because:

1. Photos are usually JPEG — Cameras and phones default to JPEG, so EXIF data (including GPS) is standard
2. Multiple metadata standards — JPEG supports EXIF, IPTC, XMP, and ICC simultaneously
3. Editing software — Photo editors add extensive metadata to JPEG files
4. Thumbnails — JPEG EXIF data often includes an embedded thumbnail image

PNG files tend to have less metadata because:

1. Screenshots and graphics — Most PNG files are screenshots or designed graphics, not photos
2. No IPTC — PNG doesn't support the IPTC standard
3. Newer EXIF support — The eXIf chunk was only standardized in 2017, so many tools don't add it

Privacy Implications

JPEG — Higher Risk

• Almost always contains camera info
• Frequently contains GPS coordinates
• Multiple layers of metadata (EXIF + IPTC + XMP)
• Editing history can be extensive

PNG — Lower Risk (Usually)

• Screenshots rarely contain sensitive metadata
• GPS data is uncommon
• But: PNG files converted from photos may carry full EXIF data
• Text chunks can contain unexpected information (AI prompts, software details)

How Metadata Removal Differs

Stripping JPEG Metadata

Remove all APP markers (APP0 through APP15) and COM markers. Keep only:

• SOI (Start of Image)
• DQT (Quantization tables)
• DHT (Huffman tables)
• SOF (Frame header — dimensions and color info)
• SOS (Start of Scan — actual image data)

Stripping PNG Metadata

Remove all ancillary chunks. Keep only:

• IHDR (Image header — dimensions, color type, bit depth)
• PLTE (Palette, if indexed color)
• tRNS (Transparency, if used)
• IDAT (Compressed image data)
• IEND (End marker)

Both approaches are used by our metadata removal tool to produce the cleanest possible output.

When to Use Each Format

Use JPEG for:

• Photographs
• Images with complex colors and gradients
• When file size matters (lossy compression is smaller)

Use PNG for:

• Screenshots
• Graphics with text
• Images requiring transparency
• When lossless quality matters

For privacy: Neither format is inherently more private. Always check and strip metadata regardless of format.