In Photoshop and Painter I can use the "Place" function to insert an image to a layer in an open file. In ArtRage I can "import a file to a layer". I think Krita can do with that function too. In a future version? I hope

Layer/New/Import Layer or drag and drop an image file in krita to insert it as a layer.

In the layers docker, the Insert Layer button has a drop-down list where you can pick "File Layer" - is this what you want?

File layers are different -- they are not editable, and get automatically updated when the file changes.

Oh! How I searched for it. It was there already And it was so easy! Thank you for letting me know..!