Starting from Visual Composer version 4.6 it is possible to add filter to image elements within Visual Composer adapted Media Library. There are currently 20+ image filters available for use in any Visual Composer element which uses Media Library as a source for image display.
Note: Image Filters do not replace original image instead making duplication of the original image and applying filter to it.
Image Filter Adding - Video Tutorial
In the video below you can see how you can quickly add Image Filters to your WordPress page by applying filter to Single Image.