I have a recycler view in my app with 300+ images in it and i am trying to improve it's performance. Should i use an image loading library for loading these images instead of just doing imageView.setImageResource(..)? Will that help?
There are several libraries available that can load images into ImageViews smoothly.
Glide is a great library with many image loading features. https://bumptech.github.io/glide/
Picasso is another library with similar features. http://square.github.io/picasso/
I wouldn't say one is better than the other, it is really just preference. They both get the job done efficiently.