Quick answer
Add the PNG or WebP to the tool above: it cuts the metadata chunks out of the file without re-encoding the picture, then re-reads the cleaned file and lists what is left. For PNG it keeps only a fixed list of chunks, so the Exif chunk, all three text chunk types and the last-modified time go. For WebP it removes the EXIF and XMP chunks.
What the specifications say
- The W3C PNG specification defines an eXIf chunk for Exif information such as shutter speed, aperture and orientation. It also defines three text chunks: tEXt (keyword and text pairs in Latin-1), zTXt (the same, compressed) and iTXt (international text in UTF-8, optionally compressed). Its predefined keywords include Author, Description, Copyright, Creation Time, Software, Source and Comment, and a tIME chunk records the last-modification time.
- The same specification calls these ancillary chunks: not strictly necessary to display the image, so a decoder can ignore them.
- The Google WebP container specification describes an extended format with a VP8X header chunk. Two flag bits say whether the file holds Exif metadata and XMP metadata. Optional EXIF and XMP chunks hold the metadata, after the image data. A separate ICCP chunk holds the ICC colour profile.
We found no source on how many PNG screenshots carry these chunks, so we make no claim about that. The PNG specification only shows that any PNG can hold Exif and text chunks, such as Software and Creation Time, if the program that saved it wrote them.
What the tool removes and keeps
PNG
Removed: every chunk that is not on a fixed keep list. That covers eXIf, tEXt, zTXt, iTXt and tIME, any other chunk type not on the list, and anything after the end chunk. Kept: IHDR, PLTE, IDAT, IEND, tRNS, gAMA, cHRM, sRGB, iCCP (the ICC profile), sBIT, pHYs, bKGD, hIST, the animation chunks acTL, fcTL and fdAT, and cICP, mDCV and cLLI. No rotation flag is written back, so an Exif orientation inside a PNG goes with the rest.
WebP
Removed: the EXIF and XMP chunks. The tool also clears the Exif and XMP flags in the VP8X header and rewrites the RIFF size. Kept: every other chunk unchanged, including the ICCP colour profile. No rotation flag is written back here either.
JPEG, for comparison
Removed: APP1 (Exif and XMP blocks), comment segments, APP3 to APP13 (including the IPTC and Photoshop block), APP15, APP2 other than the ICC profile, the JFXX thumbnail and any data after the end of the image. Kept: the other segments needed to decode the picture, the JFIF header and the ICC profile. A rotation flag other than normal is written back as a minimal Exif segment so the photo stays upright.
In all three formats the pixels are never decoded or re-encoded, so there is no quality loss. GIF is not supported.
Clean the photo before you send it
- Open the tool above and add your PNG or WebP files, up to 5 at a time. It runs entirely in your browser and your files are never uploaded.
- Read the before list. For a PNG it shows Exif details, text chunks by keyword and the last-modified date; for a WebP, Exif details and any XMP block. An empty list means the file had none.
- Download the cleaned copy.
- Check the after list. The tool re-reads the cleaned file to show what is left.
- Send the cleaned file instead of the original.
What this does not remove
- What is visible in the picture. A screenshot can show names, addresses or messages on screen. Crop or retake it if that matters.
- The file name. The tool does not rename files, so any date or place in the name stays.
- Copies stored elsewhere. Cloud storage, backups and the recipient's copy of a file you already sent are out of its reach.
To see what a file holds first, read how to see what metadata a photo has. On a desktop, see removing EXIF on Windows or on a Mac.