README.md

@@ -111,6 +111,21 @@ with a private address can choose the address it is counted by through its own
 its own address is trusted too. Setting `trusted_proxies` to the proxy's own
 address closes this.
 
+### Image Metadata
+
+pixa decodes and re-encodes every image it serves, and removes all metadata from
+the output: EXIF (GPS position, camera make, model and serial number, capture
+time, embedded thumbnail), XMP, IPTC and the ICC colour profile. This cannot be
+turned off.
+
+- The `orig` format means the source's own format, not the source's bytes: an
+  `orig` image is re-encoded and stripped like any other.
+- An image with an EXIF orientation is turned upright first, so it displays the
+  same without the tag; a requested size applies to the upright image.
+- An image with an ICC profile is converted to sRGB first, since clients show an
+  image with no profile as sRGB. Colours outside sRGB, such as the most
+  saturated ones in a Display P3 photo, are clipped.
+
 ### Source Hosts
 
 Source hosts may be allowlisted in the configuration. Non-allowlisted

TODO.md

@@ -30,6 +30,12 @@ exhaustion
 
 # Completed Steps
 
+- 2026-09-28 strip metadata from processed images (closes #82): every output is
+  exported with govips' `StripMetadata`, so it carries no EXIF, XMP, IPTC or ICC
+  profile; the image is first turned upright with `AutoRotate` (before sizes are
+  worked out) and, when it has an ICC profile, converted to sRGB; the `orig`
+  format is re-encoded and stripped like any other, as pixa never serves the
+  source bytes; there is no setting to keep metadata; documented in `README.md`.
 - 2026-09-28 rate limit the login form (closes #66): `POST /` is limited to 5
   attempts per minute per client address, and an attempt over the limit is
   refused with 429 and a `Retry-After` header; the address is the one
@@ -251,7 +257,6 @@ exhaustion
 
 # Future Steps
 
-- P1: strip EXIF and other metadata from processed images (privacy)
 - P2: security
     - referer blacklist
     - per-IP rate limiting on the image routes

internal/imageprocessor/imageprocessor.go

@@ -161,6 +161,13 @@ func (p *ImageProcessor) Process(
 	}
 	defer img.Close()
 
+	// Turn the image upright now: encode strips the EXIF orientation tag,
+	// and sizes below must be worked out on the upright image.
+	err = img.AutoRotate()
+	if err != nil {
+		return nil, fmt.Errorf("failed to auto-rotate: %w", err)
+	}
+
 	// Get original dimensions
 	origWidth := img.Width()
 	origHeight := img.Height()
@@ -404,6 +411,21 @@ func (p *ImageProcessor) encode(
 		return nil, fmt.Errorf("%w: %s", ErrUnsupportedOutputFormat, format)
 	}
 
+	// Stripping drops the ICC profile as well, and clients show an image
+	// with no profile as sRGB, so convert to sRGB first. "srgb" names
+	// libvips' built-in profile; govips' own sRGB path variable is set on
+	// first use but read without a lock, so concurrent requests race on it.
+	if img.HasICCProfile() {
+		err := img.TransformICCProfileWithFallback("srgb", "srgb")
+		if err != nil {
+			return nil, fmt.Errorf("failed to convert to sRGB: %w", err)
+		}
+	}
+
+	// Drop EXIF, XMP, IPTC and the ICC profile. govips ignores this for
+	// GIF, which carries none of them.
+	params.StripMetadata = true
+
 	output, _, err := img.Export(&params)
 	if err != nil {
 		return nil, err