zed-industries/zed · error

unsupported image MIME type `{}`

Error message

unsupported image MIME type `{}`

What it means

Validation in LanguageModelImage::from_base64_image: the supplied MIME type string is not one the `image` crate recognizes (image::ImageFormat::from_mime_type failed), so the base64 payload cannot be decoded into a model image. The image attachment's MIME type is missing, malformed, or an unsupported type (e.g. SVG or text).

Source

Thrown at crates/language_model/src/request.rs:61

                ImageFormat::Webp => image::ImageFormat::WebP,
                ImageFormat::Gif => image::ImageFormat::Gif,
                ImageFormat::Bmp => image::ImageFormat::Bmp,
                ImageFormat::Tiff => image::ImageFormat::Tiff,
                ImageFormat::Ico => image::ImageFormat::Ico,
                ImageFormat::Pnm => image::ImageFormat::Pnm,
                ImageFormat::Svg => return None,
            };
            let dynamic_image =
                image::load_from_memory_with_format(data.bytes(), format).log_err()?;
            language_model_image_from_dynamic_image(dynamic_image)
                .log_err()
                .flatten()
        })
    }

    fn from_base64_image(data: &str, mime_type: &str) -> Result<Option<LanguageModelImage>> {
        let format = image::ImageFormat::from_mime_type(mime_type)
            .ok_or_else(|| anyhow!("unsupported image MIME type `{}`", mime_type))?;
        let bytes = base64::engine::general_purpose::STANDARD.decode(data.as_bytes())?;
        let dynamic_image = image::load_from_memory_with_format(&bytes, format)?;
        language_model_image_from_dynamic_image(dynamic_image)
    }
}

fn language_model_image_from_dynamic_image(
    dynamic_image: image::DynamicImage,
) -> Result<Option<LanguageModelImage>> {
    let width = dynamic_image.width();
    let height = dynamic_image.height();
    let image_size = size(DevicePixels(width as i32), DevicePixels(height as i32));

    // First apply any provider-specific dimension constraints we know about (Anthropic).
    let mut processed_image = if image_size.width.0 > ANTHROPIC_SIZE_LIMIT as i32
        || image_size.height.0 > ANTHROPIC_SIZE_LIMIT as i32
    {
        let new_bounds = ObjectFit::ScaleDown.get_bounds(

View on GitHub (pinned to f4178619ac)

Solutions

1. Ensure the image attachment carries a standard MIME type such as image/png, image/jpeg, image/webp, or image/gif
2. Strip parameters/whitespace from the MIME string if present (from_mime_type expects a bare type)
3. Convert unsupported formats (e.g. SVG) to PNG before attaching
4. Validate the MIME type at ingestion instead of at send time

When it happens

Trigger: Thrown at crates/language_model/src/request.rs:61 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of zed-industries/zed@f4178619ac (2026-08-20). Data as JSON: /api/errors/49e0ff95468e4f86. Report an issue: GitHub.