[Vuejs]-Vue js not updating view with files data but able to console log

I’m not sure your Vue instance will think the form.image is reactive as it is a property of a SparkForm instance.

You might want to test forcing reactivity in imageChanged on the image property like so:

$this.$set($this.form, 'image', files[0];

https://v2.vuejs.org/v2/guide/reactivity.html#Change-Detection-Caveats