d2phap/ImageGlass · warning · NotSupportedException

IGE_002

IGE_002

Error message

IGE_002: Unsupported image format.

What it means

Thrown by MagickCodec.LosslessCompress when Magick.NET's ImageOptimizer does not support the file. ImageOptimizer only losslessly rewrites a small set of formats (primarily JPEG and PNG); IsSupported returns false for everything else and the method throws NotSupportedException tagged IGE_002. A null/blank path returns false earlier instead of throwing.

Source

Thrown at source/ImageGlass.Lib/Common/Photoing/Codecs/MagickCodecs/MagickCodec.cs:1284

    /// <summary>
    /// Performs lossless compression on the specified file using Magick.NET.
    /// If the new file size is not smaller, the file won't be overwritten.
    /// </summary>
    /// <returns>True when the image could be compressed otherwise false.</returns>
    /// <exception cref="NotSupportedException"></exception>
    public static bool LosslessCompress(string? filePath)
    {
        if (string.IsNullOrWhiteSpace(filePath)) return false;

        var fi = new FileInfo(filePath);
        var opt = new ImageOptimizer()
        {
            OptimalCompression = true,
        };

        // check if the format is supported
        if (!opt.IsSupported(fi)) throw new NotSupportedException("IGE_002: Unsupported image format.");

        return opt.LosslessCompress(fi);
    }

}

View on GitHub (pinned to 4a3c4fecef)

Solutions

1. Pre-check support the same way the method does: if (new ImageOptimizer().IsSupported(new FileInfo(path))) before calling, and skip otherwise.
2. Filter batch inputs to JPEG/PNG before invoking LosslessCompress.
3. Wrap the call in try/catch (NotSupportedException) and continue the batch instead of aborting.
4. For unsupported formats, fall back to a lossy re-encode via MagickCodec.SaveAsync if compression is mandatory.

Example fix

// before
MagickCodec.LosslessCompress(filePath);

// after
var opt = new ImageOptimizer { OptimalCompression = true };
if (opt.IsSupported(new FileInfo(filePath)))
{
    MagickCodec.LosslessCompress(filePath);
}

var fi = new FileInfo(filePath);
var supported = new ImageOptimizer { OptimalCompression = true }.IsSupported(fi);
if (!supported) return; // skip silently

try { MagickCodec.LosslessCompress(filePath); }
catch (NotSupportedException ex) when (ex.Message.Contains("IGE_002"))
{ /* skip unsupported file in a batch */ }

When it happens

Trigger: Calling LosslessCompress on a GIF, WEBP, BMP, TIFF, HEIC, RAW, SVG, or any format outside the optimizer's supported set; running the built-in LosslessCompression tool on a mixed batch without filtering.

Common situations: Batch compression tool invoked on a folder containing animation/image formats the optimizer cannot touch; user expects 'lossless compress' to apply to every image type; plugin-owned format passed to the built-in compressor.

Related errors

• The base64 content is invalid.
• IGE: Unsupported image format.
• IGE: Unsupported image format.
• IGE_002
• IGE: '{codec.CodecName}' could not write the image. {result.

AI-assisted analysis of d2phap/ImageGlass@4a3c4fecef (2026-08-13). Data as JSON: /api/errors/1d30166a60dcb82d. Report an issue: GitHub.