Bun.Image as an additional, self-hosted provider alongside ipx

Now that Bun has a dedicated image module (Bun.Image), the ability to utilize it as an additional self-hosted provider alongside ipx is now a possibility.

It is an image resizing pipeline built into the Bun runtime itself with an API similar to sharp.

The benefit is that it allows the potential to both reduce dependencies and improve performance.

Proposal

• Add bun / bunStatic, mirroring ipx / ipxStatic.
• Use same URL grammar (/_bun/<modifiers>/<src>), with the same modifier names and same option shape, providing a simple config change option to move between ipx and Bun as the self-hosted provider.
• A new 'auto' provider option can auto-resolve Bun.Image instead of hard-wiring ipx as the default provider if the bun Nitro preset is used, or the build runs with Bun.
• Make ipx an optional peer dependency rather than an optional dependency, so a Bun deployment installs only what's needed.

What Bun.Image cannot do yet

Bun.Image is currently (as of 9/2/2026) only a subset of sharp's capabilities:

• Resize fits are fill and inside only. cover, contain, and outside are not available yet, but PRs are upstream for this functionality
• Some modifiers do not exist yet (blur, sharpen, trim, extend, position, tint and a few more).
• AVIF and HEIC encoding still depend on OS codecs. GIF and TIFF outputs are unsupported. SVG and animated WebP formats will need to fallback to ipx.

Documentation will be needed for the bun provider, its usage, and limitations.

Start by locating the existing ipx/ipxStatic provider implementation, its URL grammar and configuration, then compare those interfaces with Bun.Image. Done means a bun/bunStatic provider, optional ipx peer dependency, auto provider selection, fallback and limitation handling, and documentation covering usage and constraints.