gohugoio/hugo · error

%q is not a valid resample filter

Error message

%q is not a valid resample filter

What it means

The `resampleFilter` in the `[imaging]` config selects the resampling kernel (box, lanczos, catmullrom, mitchellnetravali, linear, nearestneighbor, gaussian, etc.) via the imageFilters map; an unknown name fails config decode. Note a quirk in the source: the error prints the zero-value `filter` variable rather than the configured string, so the message may show `""` or an unhelpful value instead of what you typed (resources/images/config.go:229).

Source

Thrown at resources/images/config.go:229

			return i, nil, err
		}

		i.BgColor, err = hexStringToColorGo(i.Imaging.BgColor)
		if err != nil {
			return i, nil, err
		}

		if i.Imaging.Anchor != "" {
			anchor, found := anchorPositions[i.Imaging.Anchor]
			if !found {
				return i, nil, fmt.Errorf("invalid anchor value %q in imaging config", i.Imaging.Anchor)
			}
			i.Anchor = anchor
		}

		filter, found := imageFilters[i.Imaging.ResampleFilter]
		if !found {
			return i, nil, fmt.Errorf("%q is not a valid resample filter", filter)
		}

		i.ResampleFilter = filter

		return i, i.Imaging, nil
	}

	ns, err := config.DecodeNamespace[ImagingConfig](in, buildConfig)
	if err != nil {
		return nil, err
	}
	return ns, nil
}

func DecodeImageConfig(options []string, defaults *config.ConfigNamespace[ImagingConfig, ImagingConfigInternal], sourceFormat Format) (ImageConfig, error) {
	var (
		c   ImageConfig = newImageConfig()
		err error

View on GitHub ↗ (pinned to 8a468df065)

Solutions

1. Use a supported filter name such as `box`, `lanczos`, `catmullrom`, `mitchellnetravali`, `linear`, `nearestneighbor`, or `gaussian`.
2. Delete the resampleFilter key to fall back to the default (box).
3. If the message shows an empty/odd value, check your actual config string — the error text prints the wrong variable, so trust your config file, not the quoted value.

Example fix

# before
[imaging]
resampleFilter = "bicubic"

# after
[imaging]
resampleFilter = "catmullrom"

valid := map[string]bool{"box": true, "lanczos": true, "catmullrom": true, "mitchellnetravali": true, "linear": true, "nearestneighbor": true, "gaussian": true, "hermite": true, "bspline": true, "hann": true, "hamming": true, "blackman": true, "bartlett": true, "welch": true, "cosine": true}
if !valid[strings.ToLower(filter)] { /* fix imaging.resampleFilter */ }

When it happens

Trigger: `[imaging]\nresampleFilter = "bicubic"` or any name absent from imageFilters; also an explicitly empty string, since only the absent key gets the default (box).

Common situations: Using filter names from other tools (ImageMagick's `bicubic`, `triangle` spellings); typos like `lanczos3`; setting the key to an empty string via templated config.

Related errors

• invalid anchor value %q in imaging config
• config needs a filename
• invalid color code: %q
• imaging.avif.compression must be one of lossy or lossless, g
• imaging.avif.quality must be between 1 and 100 inclusive, go

AI-assisted analysis of gohugoio/hugo@8a468df065 (2026-07-31). Data as JSON: /data/errors/d549dbedb147e497.json. Report an issue: GitHub ↗.