what is the best way to verify an uploaded image is indeed an

Hi,
This does not work either. Firefox always sends Mime type based on file
extension. IE does send Mime type regardless of file extension, but this
solution only works if all your clients use IE.
Isn't there a way to verify image on the server side?
"Walter Wang [MSFT]" wrote:

> Hi,
> You should check the uploaded file's ContentType to determine the real fil
e
> type, the ContentType will return "image/x-png" for a PNG file and
> "image/gif" for a GIF file regardless the file extension:
> protected void Button1_Click(object sender, EventArgs e)
> {
> if (FileUpload1.HasFile)
> {
> string ct = FileUpload1.PostedFile.ContentType;
> Response.Write(ct);
> }
> }
>
> Hope this helps.
>
> Sincerely,
> Walter Wang (wawang@dotnet.itags.org.online.microsoft.com, remove 'online.')
> Microsoft Online Community Support
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>Hi,
Thank you for your quick update. I understand that the MIME ContentType
approach is not what you wanted. I will do some further research to see if
there's any other methods.
By the way, I'm not able to find the issue you mentioned that IE will load
a .PNG file faked in .GIF file type and the script will be executed by
JScript engine. Would you please let me know where you see the information
on this? Thanks.
Regards,
Walter Wang (wawang@.online.microsoft.com, remove 'online.')
Microsoft Online Community Support
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