How to change the same setting in multiple material nodes at the same time?

When you select an Image Texture node in the node editor, there’s a property in the N panel called “Use Alpha”. I want to disable this setting in multiple texture nodes in multiple materials. Usually holding the Alt key while clicking something allows changing properties of active and selected objects, but this doesn’t work in the node editor. Is there any other way to do this? I have to change hundreds of texture nodes, selecting every single one is rather tedious.

Use Alpha is a setting per image, only also accessible in an image texture node’s n panel. It’s the same setting in the n panel of the image editor. If you have multiple materials with the same image in an image texture node and change it in one material, it will be changed for all alther materials also that contain that image.

If you want to change it for a lot of different images, you could use python. Here’s a quick snippet that changes Use Alpha to off for every image currently in Blender. Paste those lines into a new text in Blender’s text editor and hit Run Script.

import bpy

for img in
    img.use_alpha = False

To set it to on, change False to True.