how to get the a value of the resolution of an image in blender compositor?

Question

I am creating a node group and this node group required the value of the X resolution of the image that the user will put so the user should put half the value of the X resolution but I want to make this automatic so the user should only put the image and half the value of X resolution will automatically generated,so how can I get the value of X resolution of the image that the user will put.

Answer 1

You can use a driver to easily get the render resolution from the scene, for a user selected image it gets tricky as you will need to know the name of the image or the image node to reference it's resolution.

I think you could achieve that with a custom python node but at this stage they don't integrate well, they don't update when a connected node changes so need manual updating which can lead to errors.