microsoft/semantic-kernel · error · NotSupportedException

The provided quality '{quality}' is not supported.

Error message

The provided quality '{quality}' is not supported.

What it means

The image quality string is matched case-insensitively against STANDARD, HIGH, HD, MEDIUM, LOW, AUTO. Null is allowed (returns null, omitting the parameter). Any other value throws NotSupportedException before the request is sent.

Source

Thrown at dotnet/src/Connectors/Connectors.OpenAI/Core/ClientCore.TextToImage.cs:128

        => size is null
            ? null
            : new GeneratedImageSize(size.Value.Width, size.Value.Height);

    private static GeneratedImageQuality? GetGeneratedImageQuality(string? quality)
    {
        if (quality is null)
        {
            return null;
        }

        return quality.ToUpperInvariant() switch
        {
            "STANDARD" => GeneratedImageQuality.Standard,
            "HIGH" or "HD" => GeneratedImageQuality.High,
            "MEDIUM" => GeneratedImageQuality.MediumQuality,
            "LOW" => GeneratedImageQuality.LowQuality,
            "AUTO" => GeneratedImageQuality.Auto,
            _ => throw new NotSupportedException($"The provided quality '{quality}' is not supported.")
        };
    }

    private static GeneratedImageStyle? GetGeneratedImageStyle(string? style)
    {
        if (style is null)
        {
            return null;
        }

        return style.ToUpperInvariant() switch
        {
            "VIVID" => GeneratedImageStyle.Vivid,
            "NATURAL" => GeneratedImageStyle.Natural,
            _ => throw new NotSupportedException($"The provided style '{style}' is not supported.")
        };
    }

View on GitHub (pinned to c028a0c7dc)

Solutions

1. Use one of: standard, high, hd, medium, low, auto (case-insensitive).
2. Leave Quality unset/null if you don't need to override the default.
3. Upgrade the connector package if a newer quality level is available upstream.

Example fix

// before
var settings = new OpenAITextToImageExecutionSettings { Quality = "ultra" };

// after
var settings = new OpenAITextToImageExecutionSettings { Quality = "hd" };

static readonly HashSet<string> SupportedQualities = new(StringComparer.OrdinalIgnoreCase)
{
    "standard", "high", "hd", "medium", "low", "auto"
};

void ValidateQuality(string? quality)
{
    if (quality is not null && !SupportedQualities.Contains(quality.Trim()))
        throw new ArgumentOutOfRangeException(nameof(quality),
            $"Quality must be one of: {string.Join(", ", SupportedQualities)} (or null)");
}

try { await imageService.GetTextToImageAsync(prompt, settings); }
catch (NotSupportedException ex) when (ex.Message.Contains("quality"))
{
    settings.Quality = null;
    await imageService.GetTextToImageAsync(prompt, settings);
}

When it happens

Trigger: Passing an OpenAITextToImageExecutionSettings.Quality value not in the allowed set, e.g. 'ultra', 'best', or a numeric like '1'.

Common situations: Using a quality token from newer OpenAI API docs not yet mapped by the installed connector version. Passing a quality name that only applies to a different model (e.g. DALL-E 2 values used with DALL-E 3).

Related errors

• The provided style '{style}' is not supported.
• The provided response format '{formatString}' is not support
• The generated image has no valid content.
• Invalid image size: {size.width}x{size.height}.
• Prompt is required.

AI-assisted analysis of microsoft/semantic-kernel@c028a0c7dc (2026-08-13). Data as JSON: /api/errors/389d9a6086d19d0c. Report an issue: GitHub.