JPEG is a common image format that uses lossy compression to reduce file size while keeping pictures visually usable. That makes it efficient for websites, messaging, and storage, but it also means the file is more than just “a photo.” A JPEG can contain compressed image data plus metadata and structural markers that software must parse correctly.
In cyber security, JPEG matters because attackers may abuse image handling in applications, email filters, or content pipelines. A malicious file can hide payloads in metadata, exploit weaknesses in image libraries, or be crafted to look harmless while triggering parser bugs. Defenders inspect JPEGs with file-type validation, sandboxed processing, metadata stripping, and patched libraries. Understanding JPEG helps security teams reduce attack surface in systems that accept user-uploaded media.