how to remove exif and gps data from your photos

a photo file is more than the picture. next to the pixels sits a block of metadata called exif, written by the camera. most people have never looked at it.

what's in there

• gps coordinates -- latitude and longitude, often accurate to a few metres. this is the one that matters. it is precise enough to name a building.
• date and time, usually with your timezone offset attached.
• device make and model. the model alone is weak, but it ties photos together: two pictures from the same phone share it.
• lens, exposure, orientation, editing software -- and on some phones a thumbnail of the original image. that thumbnail can survive cropping in a few older tools.

how to see it yourself

you don't need a special tool. on iphone, open a photo, then swipe up or tap the info button -- if a map appears, the file has coordinates. on android, open a photo in google photos and tap info. on windows, right-click the file → properties → details. on mac, open it in preview → tools → show inspector.

try it once on a photo you took at home. that is more convincing than anything written here.

how to remove it

• iphone: in photos, tap share, then "options" at the top, and turn off "location". that strips coordinates from the copy you send -- not from the original.
• android: in google photos, open the photo → info → remove location. the exact labels vary by manufacturer.
• windows: right-click → properties → details → "remove properties and personal information".
• anywhere: take a screenshot of the photo. you get a new file with none of the original metadata. crude, some quality lost, but it works every time.

better still: turn capture off at the source. camera settings → location / geotagging. then there is nothing to strip later.

what stripping it doesn't do

removing exif removes what the file says about you. it does nothing about what the picture shows -- the window, the street sign, the reflection. and it does nothing about the image being matched against other copies of itself later. that part is how people get found from a photo.

how sissy-haven handles this

you don't have to remember any of the above. every upload is re-encoded on our side. metadata is thrown away, not copied across. the file other people receive has no coordinates, no timestamp, and no device in it. there is a script in the repo that pushes a photo with coordinates through the real pipeline and checks that nothing survives. we run it whenever that pipeline changes.

we also never store a precise location for you. If you decide to give us your location to match picture with the "close to me" filter, the GPS position is rounded to a roughly 2.5 km square the moment it arrives, and only the square is kept. how matching works explains why that's enough.

if you'd rather not think about any of this every time, an account takes a minute and no email address.