JeffreySu/WeiXinMPSDK · error · ArgumentException

商家名片会员图片仅支持 JPG、JPEG、BMP 或 PNG。

Error message

商家名片会员图片仅支持 JPG、JPEG、BMP 或 PNG。

What it means

WeChat's brand member card image upload only accepts JPG, JPEG, BMP, and PNG images. ValidateBrandMemberImageFileName inspects the fileName extension (case-insensitive) and throws ArgumentException for any other extension, preventing a guaranteed-to-fail upload.

Solutions

1. Convert the image to JPG or PNG before upload (e.g. via SkiaSharp/ImageSharp).
2. Validate and normalize the extension in your own pipeline before calling the API.
3. Rename the file to include a supported extension only when the actual format matches — never just rename a GIF to .png.

Example fix

// before
await apis.UploadMemberImageAsync(brandId, bytes, "avatar.webp");
// after
var pngBytes = ImageConversion.ConvertToPng(bytes); // transcode first
await apis.UploadMemberImageAsync(brandId, pngBytes, "avatar.png");

var ext = Path.GetExtension(fileName)?.ToLowerInvariant();
if (ext is not (".jpg" or ".jpeg" or ".bmp" or ".png"))
    throw new ArgumentException("Member images must be JPG, JPEG, BMP or PNG.");

bool supportedImage(string? f) =>
    Path.GetExtension(f ?? "")?.ToLowerInvariant() is ".jpg" or ".jpeg" or ".bmp" or ".png";

try { await apis.UploadMemberImageAsync(brandId, bytes, fileName); }
catch (ArgumentException ex) when (ex.Message.Contains("JPG")) { return ConvertToJpg(bytes); }

When it happens

Trigger: Calling UploadMemberImageAsync with a file name whose extension is .gif, .webp, .heic, .tiff, or has no extension at all.

Common situations: Users uploading modern formats (WebP/HEIC) from phones; server-side transcoding pipelines passing original names; file names generated without extensions.

Related errors

• 方法路径不能为空
• 无效的方法路径格式
• 单击按钮的key不能为空！
• 文件名不能为空。
• 接收方类型为 MERCHANT_ID 时，name 必填。

AI-assisted analysis of JeffreySu/WeiXinMPSDK@be573f6f94 (2026-09-12). Data as JSON: /api/errors/6d2d19cb9222ef5b. Report an issue: GitHub.

Appendix: source

Thrown at src/Senparc.Weixin.TenPay/Senparc.Weixin.TenPayV3/Apis/BrandMemberCard/BrandMemberCardApis.cs:374

        }

        private static void ValidateBrandMemberImageFileName(string fileName)
        {
            if (string.IsNullOrWhiteSpace(fileName))
            {
                throw new ArgumentException("文件名不能为空。",
                    nameof(fileName));
            }

            switch (Path.GetExtension(fileName)?.ToLowerInvariant())
            {
                case ".jpg":
                case ".jpeg":
                case ".bmp":
                case ".png":
                    return;
                default:
                    throw new ArgumentException(
                        "商家名片会员图片仅支持 JPG、JPEG、BMP 或 PNG。",
                        nameof(fileName));
            }
        }

        private Task<T> PostAsync<T>(string path, object data, int timeOut)
            where T : ReturnJsonBase, new()
        {
            return _request.RequestAsync<T>(GetUrl(path), data, timeOut);
        }

        private Task<T> PatchAsync<T>(string path, object data, int timeOut)
            where T : ReturnJsonBase, new()
        {
            return _request.RequestAsync<T>(GetUrl(path), data, timeOut,
                ApiRequestMethod.PATCH);
        }

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