Dotnet Core 2.2 libgdipplus异常

我在openshift上运行dotnet core 2.2 Web api，我有一个返回FileResult的api方法。该文件是使用epplus生成的。但是，在对应用程序进行容器化之后，端点将返回以下错误。我相信如果使用system.drawing库，则会发生此异常，但是我没有使用任何system.drawing功能。

System.TypeInitializationException：“ Gdip”的类型初始值设定项引发了异常。---> System.DllNotFoundException：无法加载DLL'libgdiplus'：找不到指定的模块。

public async Task<FileResult> GetPSACostCaseAndFeedData([FromQuery] int caseId, [FromQuery] int proposalId, [FromQuery] int equipmentId)
        {
            try
            {
                var queryParams = new Dictionary<string, string> { { "caseId", caseId.ToString() }, { "proposalId", proposalId.ToString() }, { "equipmentId", equipmentId.ToString() } };
                var restObj = _restFactory.createRestRequest(Method.GET, "ProposalService/PSACostData/GetPSACostCaseAndFeedData", queryParams);
                Console.WriteLine("Base URL - "  + restObj.Item2.BaseUrl);
                var response = await restObj.Item2.ExecuteTaskAsync(restObj.Item1);
                if (response.StatusCode == HttpStatusCode.OK)
                {
                    var result = JsonConvert.DeserializeObject<PSACostCaseDetailsResponse>(response.Content);
                    Console.WriteLine("result -" + response.Content.ToString());
                    Console.WriteLine("start writing file");
                    var excelPackage = await _iPSACostExcelHelper.PopulatePsaCostFile(result, Path.Combine(_hostingEnvironment.ContentRootPath, "App_data", "PSACOST_V9.2.2.xlsm"));
                    Console.WriteLine("finished writing file");
                    return await Task.FromResult(File(_excelHelper.ConvertWorkBookToByteArray(excelPackage), ContentTypeEnums.excel, result.customerInformationModel.ProposalNum + "_" + result.caseDataModel.CaseNm + ".xlsm"));
                }
                throw new Exception("There is no PSA cost data for this case");
            }

“完成的写入文件”行确实被打印到标准输出，此后的行失败。有人可以帮助我了解这里出了什么问题吗？为什么FileResult类型的返回方法需要system.drawing？

下面也是我的dockerfile。

FROM mcr.microsoft.com/dotnet/core/aspnet:2.2.7-alpine3.10
LABEL pipelineName="PSACOST.API" \
      pipelineKey="UMAOKJOH" \
      offeringKey="KKWEECBH"
RUN apk upgrade -U
EXPOSE 5000
ENV ASPNETCORE_URLS=http://*:5000
WORKDIR /app
COPY . /app
USER guest
ENTRYPOINT ["dotnet", "PSACOST.API.Web.dll"]