How can i merge widget into image or video

Question

i am displaying image in my UI using mage.network widget, and display Text widget in Stack like following

  Stack(
      alignment: Alignment.center,
      children: [
        Image.network('myImage'),
        Text('Hello world')
      ],
    );   

also the same idea but with video

 Stack(
      alignment: Alignment.center,
      children: [
        VideoPlayer('myVideoFile'),
        Text('Hello world')
      ],
    );

now my question : How can i merge ANY Widget that add into stack (in my case Text('Hello world')) into one final result file ?

in other word : if i want to save my image or video into my storage so Of course they will be saved separately from the widgets they have inside Stack . but How could i merge the widgets with them and became one file? so when i save them to my storage and want to open them again i will find the widgets already merged with them

the only way i have now is to screenshot my screen using screenshot plugin and save the result as one file . and the same with video but with record_screen plugin But it is a very bad experience

What should I look for to handle this work? any plugin ? Any suggestions?