You said you want to call loadImages() from somewhere in your code (I think your words were 'from a different file').
loadImages is a method of your PlotPanel class (correct?).
In order to call loadImages you need to call it on a specific *instance* of the PlotPanel class.
Now what you tried to do first was to create a new *instance* of PlotPanel and then call loadImages
Code:
var a = Ext.create('GraphPanel', {});
a.loadImages(url);
I tried to explain why that doesn't make much sense! (see my previous post)
I *think* that you rather wanted to call loadImages to load images into your *existing* panel on the page.
In a previous code snippet you had assigned the id 'plotPanel' to your panel instance.
If this is still the case, you can fetch this *instance* with Ext.getCmp('plotPanel').
Code:
Ext.create('Ext.window.Window', {
id: 'myWindow',
title: 'Gotcha!',
width: 200,
// ...
});
// anywhere else on that page, but AFTER the window has been created (and probably rendered)
var window = Ext.getCmp('myWindow');
console.log(window.title); // says 'Gotcha!'
Of course I might be a bit confused about your panels' names and class names (plotPanel, graphPanel, etc).
But I hope it makes sense to you.