New Post: Append multiple rows of images

I have a string array where each element should be a line in my output image. For example

string[] input= new string[2] {"Hello", "World"};

I need to iterate on this array and create an output image (gif) where each letter uses a custom image (see the code below), I would like to have an output image with a background where my "text" is centered (vertically and horizontally)
Sample output: (with a background and centered)
Hello
World

I'm doing something like: (

foreach (var line in input) // input is the array where I have the text
{
     foreach (var letter in line) 
     {
          // Depending on the letter load the specific image
          MagickImage image = new MagickImage($"{InputPath}\\{letter}.png");

          // TODO: Allow multiple lines, the following resize and extend are just some of the tests
          // image.Resize(960, 540);
          // image.Extent(960, 540, Gravity.Center);
          // image.Extent(-5, -80 * position, 80, 540);     
         
          // When I have just one line it works very nice, just doing this:
          image.BackgroundColor = MagickColors.Transparent;                  
          collection.Add(image);
     }
     position++; // this is the current line
}

// Then I'm appending my collection horizontally and adding the background image:
using (MagickImage horizontal = collection.AppendHorizontally())
{
     horizontal.Extent(new MagickGeometry(960, 540), Gravity.Center);
     
     using (MagickImage background = new MagickImage("background.png"))
     {
          horizontal.Composite(background, CompositeOperator.DstAtop);
          horizontal.Write($"{OutputPath}\\test.png");
      }
}

Can anyone please help me with this issue appending multiple rows?

Thanks in advance