ASP.NET Core: Fetch image from external site and save on Server - image

Question

I want to fetch an image from an external site and save it on the web application´s server.
My current code downloads the file, but it won't open because of wrong format, it says.
private Uri _uri;
private HttpClient _client;
[HttpPost]
public async Task WmsExport(ExportImagePostData postData)
{
try
{
PrepareUri(postData);
ValidateUrl(postData);
PrepareRequest(postData);
await FetchImageAndSave_async(postData);
}
catch (TaskCanceledException)
{
HttpContext.Response.StatusCode = 408;
}
catch (Exception ex)
{
var statusCode = 500;
HttpContext.Response.StatusCode = statusCode;
_logger.LogError(ex, ex.Message);
}
}
private void PrepareRequest(ExportImagePostData postData)
{
_client = _customClientFactory.CreateHttpClient();
_client.BaseAddress = _uri;
_client.CopyRequestHeaders(HttpContext);
_client.DefaultRequestHeaders.Add("Accept", "image/png");
}
public async Task FetchImageAndSave_async(ExportImagePostData postData)
{
using (var contentStream = await _client.GetStreamAsync(_client.BaseAddress.OriginalString))
{
await SaveImageOnServer_async(postData, contentStream);
}
}
private async Task SaveImageOnServer_async(ExportImagePostData postData, Stream downloadStream)
{
var filename = "wmsexp" + DateTime.Now.ToString("HHmm") + "." + postData.ImageType;
var directory = "wwwroot/Images/uploads/";
var path = Path.Combine(Directory.GetCurrentDirectory(), directory, filename);
using (var outStream = new FileStream(path, FileMode.Create, FileAccess.Write, FileShare.None, 1048576, true))
{
await downloadStream.CopyToAsync(outStream);
}
}
Here is how the images look like in my folder, when I try to open them:
****SOLVED** **
I got help from Roman Marusyk, here on Stack Overflow. Thanks Roman! If you write an answer I be happy to set it as the answer!
The issue seem to have been that I added wrong HTTP-headers, and that some of my paths to the images where incorrect.