Multiple images are generated in WP-content in wordpress

  1. When you upload an image to WordPress, it generates three image sizes by default (thumbnail, medium, and large).
    Put simply, WordPress automatically resizes images to help you save bandwidth and prevent you from having to manually resize images. For example, the image size you would use for a thumbnail is much different than what you would use for an image slider on your home page. By generating multiple image sizes, WordPress makes it easier for you to select the most appropriate option for each use case.
    If you delete any of the images your site will not generate them again unless you upload same image using media uploader again.

  2. It will not affect website loading speed or performance in any way. But it will take little more space on your hosting platform.