Add image digest glossary term

content/en/image-digest.md

@@ -0,0 +1,38 @@
+---
+title: Image Digest
+status: Completed
+category: concept
+tags: ["application", "security"]
+---
+
+An image digest is a unique, content-addressable identifier for a
+[container image](/container-image/). It is a cryptographic hash (typically
+SHA-256) of the image’s manifest, as defined in the
+[OCI Image Specification](https://specs.opencontainers.org/image-spec/#overview).
+Suppose an image tag is like a nickname: a mutable, human-readable label you can
+reassign to a different image at any time. An image digest is like a
+fingerprint: it is immutable and always identifies the exact content of one
+image.
+
+## Problem it addresses
+
+Container images are commonly referenced by tags (e.g., `myapp:v1.0` or `myapp:latest`).
+Tags are convenient, but they are mutable: a registry owner can push a different image
+under the same tag at any time. This means two deployments using `myapp:latest`
+may run entirely different software, making reproducibility difficult and introducing
+security risks; for example, a compromised tag could silently deliver a malicious image.
+
+## How it helps
+
+An image digest provides a guaranteed, tamper-evident way to reference a
+container image. Because the digest is derived from the image content itself,
+any change to the image produces a different digest. By referencing an image by
+digest (e.g., `myapp@sha256:abc123...`), teams ensure they always run the exact
+same image, regardless of what happens to its tag. This is especially important
+for security audits, reproducible builds, and supply chain integrity in
+production environments.
+
+## Related terms
+
+- [Container](/container/)
+- [Container Image](/container-image/)

wordlist.txt

@@ -46,6 +46,7 @@ cpu
 cri
 critic
 crm
+cryptographic
 customizable
 cyber
 daniel
@@ -173,6 +174,7 @@ RBAC
 rdbms
 readme
 replicable
+reproducibility
 reusability
 rojopolis
 rollouts
@@ -190,6 +192,7 @@ seo
 seokho
 serverless
 sexualized
+SHA
 sidecarless
 signup
 signups