siyuan-note/siyuan · error

prepared image exceeds size limit: %d bytes

Error message

prepared image exceeds size limit: %d bytes

What it means

After all processing (resize, PNG encode, final JPEG quality-92 encode) the output STILL exceeds maxBytes. The image cannot be compressed under the cap at quality 92, so it is rejected.

Source

Thrown at kernel/util/openai.go:684

		if err = png.Encode(&output, decoded); err != nil {
			return PreparedImage{}, errors.New("encode image failed: " + err.Error())
		}
		if maxBytes <= 0 || output.Len() <= maxBytes {
			return PreparedImage{
				Data:       output.Bytes(),
				MIMEType:   "image/png",
				Width:      bounds.Dx(),
				Height:     bounds.Dy(),
				SourceSize: len(data),
			}, nil
		}
	}
	var output bytes.Buffer
	if err = jpeg.Encode(&output, decoded, &jpeg.Options{Quality: 92}); err != nil {
		return PreparedImage{}, errors.New("encode image failed: " + err.Error())
	}
	if maxBytes > 0 && output.Len() > maxBytes {
		return PreparedImage{}, fmt.Errorf("prepared image exceeds size limit: %d bytes", maxBytes)
	}
	return PreparedImage{
		Data:       output.Bytes(),
		MIMEType:   "image/jpeg",
		Width:      bounds.Dx(),
		Height:     bounds.Dy(),
		SourceSize: len(data),
	}, nil
}

// ValidateGeneratedImage 校验生成图片的格式、尺寸和体积。
func ValidateGeneratedImage(data []byte) (mimeType, extension string, err error) {
	if len(data) == 0 {
		return "", "", errors.New("generated image is empty")
	}
	if len(data) > maxGeneratedImageBytes {
		return "", "", errors.New("generated image exceeds size limit")
	}

View on GitHub (pinned to 251596fc0d)

Solutions

1. Downscale the source resolution before sending.
2. Pre-compress to a lower JPEG quality externally.
3. Raise maxBytes if the provider allows a larger upload.

img, err := util.PrepareModelImage(data, maxBytes, maxPixels, maxEdge)
if err != nil {
    log.Warnf("image too large for vision budget after encode: %s", err)
    return skipImage()
}

When it happens

Trigger: Very large or complex image whose JPEG q92 output is still over maxBytes (e.g. 20MP photo with maxBytes=1MB).

Common situations: Aggressive maxBytes combined with high-resolution input; provider with a tight upload cap.

Related errors

• image exceeds size limit: %d bytes
• image exceeds pixel limit: %d
• image data is empty
• SVG images are not accepted by multimodal models
• unsupported image type: %s

AI-assisted analysis of siyuan-note/siyuan@251596fc0d (2026-08-12). Data as JSON: /api/errors/58bd30911a538665. Report an issue: GitHub.