Fix work on Windows 7

[alexander7550]

No description provided.

[jwcloverain]

use http is not safe

[kasavaros]

use http is not safe,for this error check if the system has installed the kb3140245 update? see https://support.microsoft.com/en-us/topic/update-to-enable-tls-1-1-and-tls-1-2-as-default-secure-protocols-in-winhttp-in-windows-c4bd73d2-31d7-761e-0178-11268bb10392

This update and fix did not help me.
But there is another software - Tradeonsda and it works on Windows 7 https://github.com/TradeOnSolutions/Steam-Desktop-Authenticator

[Jessecar96]

I don't like this solution. Loading the image over plain http is not secure and can leak info about someone using SDA. A better solution would be to get the PictureBox to use TLS 1.2, if possible.

[chinap]

use this method?
see：https://stackoverflow.com/questions/24797485/how-to-download-image-from-url

test
\SteamAuth\SteamWeb.cs
on 17 line add

[DJWalker]

So... the entire problem is caused by PictureBox not always wanting to use TLS 1.2 when it loads an icon? Is the icon essential?

I agree about the HTTP fallback not being great, but could you not just catch the exception as in this patch but do nothing in the catch block, so that all you get is a missing icon but otherwise confirmations still work?