PNGJPG
PNGJPG is a non-standard, informal term used to describe a hypothetical image format that attempts to combine features of the Portable Network Graphics (PNG) and JPEG formats. It does not refer to an official specification and has no universal definition. In practical discussions, PNGJPG typically denotes one of two ideas: a dual-stream container that stores both a lossless PNG image and a lossy JPEG version within a single file, or a single image file that can be decoded as either PNG or JPEG by specialized software.
Variants and implementations vary. Some proposals describe a file wrapper that embeds a PNG data stream alongside
Technical considerations include handling of color spaces, gamma, transparency (alpha channel), and metadata. PNG supports lossless
Use cases discussed in informal discussions include archival workflows that preserve a lossless master alongside a