Supported Formats

Wallpaper Server scans and accepts the image formats built into its Go image decoders. The supported_extensions list is applied to the wallpaper service before indexing starts and controls both folder scanning and imports.

Available extensions

Extension	MIME type	Scan	Upload
.jpg	image/jpeg	Yes	Yes
.jpeg	image/jpeg	Yes	Yes
.png	image/png	Yes	Yes
.webp	image/webp	Yes	Yes

These are the registered formats, not an invitation to add arbitrary extensions. The server validates the configured allowlist rather than assuming that renaming an unsupported image file enables decoding.

Configuring accepted extensions

To limit the server to JPEG and PNG images:

config.yaml

supported_extensions:
  - .jpg
  - .jpeg
  - .png

An empty list or an unrecognised extension causes service startup validation to fail. Values are normalised to lowercase; leading dots are required. Changes take effect after a server restart, not merely an index refresh.

Unsupported files are skipped during scans and rejected on upload. For safety, the upload body is bounded and decoded image dimensions are capped at 100 megapixels; these safeguards do not eliminate the need to trust the sources of images you import.

Derived images

Thumbnails use JPEG, independent of the source format. The image variant API currently supports jpg and png output, with configurable crop/contain sizing and JPEG quality. See API endpoints and Caching and storage.