How do I convert the following remote URL to a base64 safe URL with C#?

I want to fetch remote images and do some image transformation specifically an overlay over an image with cloudinary. But cloudinary only supports 64base safe urls to overlay images. Lets say I have this following remote image URL.

https://scontent.xx.fbcdn.net/v/t1.0-9/15665479_1260320054027269_4201232212927955955_n.jpg?oh=ee01f2ec47b2e972bc12f99d988db241&oe=5946A159

How can I encode it to a 64base url? I have been through many SO questions related to the question but none of them were helped me to solve the issue.

Solution

In case you need to encode both URL and Image (may not be what you need, but might be useful sometime)

string url = "https://scontent.xx.fbcdn.net/v/t1.0-9/15665479_1260320054027269_4201232212927955955_n.jpg?oh=ee01f2ec47b2e972bc12f99d988db241&oe=5946A159";

string encodedUrl = Convert.ToBase64String(Encoding.Default.GetBytes(url));

using (var client = new WebClient())
{
    byte[] dataBytes = client.DownloadData(new Uri(url));
    string encodedFileAsBase64 = Convert.ToBase64String(dataBytes);
}