What your photos are carrying
A photo from a phone is not only pixels. The file usually also records the camera or phone model, the exact date and time, exposure settings, the orientation, sometimes the owner’s name, and often the GPS coordinates of the spot where it was taken.
The coordinates are the part that matters. A photo taken at home and posted publicly can point at your front door with a precision of a few metres.
Many platforms strip metadata on upload, which has taught people that it is handled automatically. It is not handled when you send a photo by email, hand over a file directly, attach it to a listing, or upload it to a smaller site.
What this tool shows you
For JPEG files the tool reads the file’s marker structure and reports which metadata blocks exist: EXIF, XMP, IPTC, an embedded colour profile, comments, and specifically whether the EXIF block contains GPS information. That answers the practical question, which is not “is there metadata” but “does this photo say where I was”.
It reports only what it can confirm from the file structure, and says nothing rather than guessing when a block is unusual or truncated.
How the removal works
The image is decoded, drawn onto a canvas and re-encoded. A canvas holds nothing but pixels, so every metadata block is gone by construction rather than by a list of things to delete. Nothing hidden survives, because nothing hidden is carried over.
The cost is re-compression when you choose JPEG. At quality 92 that is invisible in normal viewing. Choose PNG if you need a lossless result and can accept a much larger file.
When you want to keep the data
Metadata is not the enemy. Photographers rely on exposure data, and location makes a holiday library searchable. Strip a copy for publishing and keep your originals with everything intact. Your original files are never modified here.
Questions
Are my photos uploaded to be checked?
No, and that is the whole point. A photo you are worried about is the last file you should upload to a stranger's server. The inspection and the cleaning both happen on your device.
What exactly is removed?
Everything except the pixels. The image is redrawn and re-encoded, which drops EXIF, GPS, XMP, IPTC, comments and the colour profile. Width, height and visible content are unchanged.
Can the removal be undone?
Not from the cleaned file. Keep your original if you want the camera data; the download is a copy, your original is untouched.
Does it change image quality?
JPEG output re-compresses, so choose a high quality setting; 92 is visually indistinguishable in normal use. PNG output is lossless but produces much larger files for photographs.
Why does it say no metadata found?
Screenshots, images already processed by a social network, and most PNGs carry no EXIF block. Detailed detection is done for JPEG files; for PNG and WebP the tool cleans without listing what was there.