How in the script to apply an image on the image texture node I can’t find the answer to how to select an existing node through the script and apply the already added image without a GUI.

I have a ready-made script that opens a prepared blender file with saved materials, makes an import of the SVG curve and performs manipulations by adding these materials. 

In one of the materials I need to change one picture.
I found a code that can add a node with a new picture

import bpy
bpy.data.images.load("D:/temp/1.png", check_existing=True)
mat = bpy.context.view_layer.objects.active.active_material
tex = bpy.data.images.get('1.png')
image_node = mat.node_tree.nodes.new('ShaderNodeTexImage')
image_node.image = tex


This code created a new unconnected node and it needs to be connected to three other nodes. But I need only assign an already linked picture to the already connected node.
The solution was quite simple, though not found answer on the Internet.

import bpy
bpy.data.images.load("D:/badge/temp/1.png", check_existing=True)
mat = bpy.context.view_layer.objects.active.active_material
tex = bpy.data.images.get('1.png')
image_node = mat.node_tree.nodes["Image Texture"]
image_node.image = tex


At the same time, the desired node must be selected previously in the material so that everything works out.