Convert embedded Infopath image to html image

[Rockie]

Greetings!

I have an old Infopath system stored in SharePoint. Now I'm trying to use Power Automate to extract embedded images from there. I found how to get text part which represents image inside. So for example "x0lGQRAAA...." here is image header and image content, as I understand:

But here I stucked. I know how to create html file but cannot convert infopath encoded string to html:

<img src="data&colon;image/png;base64,x0lGQRQAAAABAAAAAAAAAPmaAAAkAAAAIQQ9BDgEPAQ..." />

Tried to use this string like this, but this does not work:

As I understand there is encoded header in this string, this is not clear file content.

Also tried to use base64ToBinary conversion and then extract content like described here

outputs('Compose_base64ToBinary')?['body/$content']

But it also does not work, base64ToBinary has same string in 'content':

 

How to convert this infopath string to something I can work. Or how to decode header and image content  (some images could have *.png type, and other *.jpg, etc.)

[Rockie]

Update:

So Infopath XML stores embedded images in base64 string, which contains file name/type and file content. Here are two embedded images:

In Infopath XML this image is stored like base64 string:

<my:group4>
    <my:field18>
        <!-- jpg-image.jpg encoded in infopath form: -->
        x0lGQRQAAAABAAAAAAAAAO+aAAAOAAAAcABuAGcALQBpAG0AYQBnAGUALgB...
    </my:field18>
</my:group4>

First part contains file name and the second is encoded image.

We can use encoded image part in html as image content like this: 

<img src="data%3Aimage/png;base64,iVBORw0KGgoAAAANSUhEUgAAABkAA..." />

But xml string in Infopath stores both filename and content in one line, so I need to read some bytes and split file name and image content

Here I put examples of InfoPath string and C# code, that decodes it and get file name/and content strings:

https://gist.github.com/Gennady-G/48d740c92593e1ce8234b4a8c3a23069

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Xml;
using System.Xml.XPath;
using System.Security.Cryptography;
using System.IO;


namespace getFilenameFromBase64
{
    class Program
    {

        // "jpg-image.jpg" file encoded in infopath xml
        private static string base64FromInfopath = "x0lGQRQAAAABAAAAAAAAAPBgAAAOAAAAa....";

        // "png-image.png"
        //private static string base64FromInfopath = "x0lGQRQAAAABAAAAAAAAAO+aAAAOAAAAc...";

        static void Main(string[] args)
        {
            // This function from Quazi Anis gets filename from encoded string
            // https://www.infopathdev.com/forums/p/15120/53720.aspx#53720
            Encoding _encoding = Encoding.Unicode;

            // Read base64 string and get header, filename and image content separately
            using (MemoryStream _memoryStream = new MemoryStream(Convert.FromBase64String(Program.base64FromInfopath)))
            {
                BinaryReader _theReader = new BinaryReader(_memoryStream);
                byte[] _headerData = _theReader.ReadBytes(16);
                int _fileSize = (int)_theReader.ReadUInt32();

                int _imageNameLength = (int)_theReader.ReadUInt32() * 2;
                byte[] _fileNameBytes = _theReader.ReadBytes(_imageNameLength);

                // here is file name decoded:
                string fileName = _encoding.GetString(_fileNameBytes, 0, _imageNameLength - 2);
                Console.WriteLine(fileName);                                                // result: "jpg-image.jpg"

                // and here is base64 data of pure image that we can use in html: <img src="data&colon;image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAqMAAAIZCAIAAAAdrK.." />
                var imageContentInBytes = _theReader.ReadBytes(_fileSize);
                var imageContentAsString = Convert.ToBase64String(imageContentInBytes);     // result: "iVBORw0KGgoAAAANSUhEUgAAAqMAAAIZCAIAAAAdrK.."

                Console.WriteLine(imageContentAsString);
            }
        }
    }
}

Here are project sources if needed:

https://github.com/Gennady-G/ExtractImageFromInfopathXml/blob/main/getFilenameFromBase64/getFilename...

Can I do something similar (make operations with bytes array) in SharePoint power automate? Or what You think I can do to decode base64 string and extract file name/type and image content from there?