Does drupal create new file in image styles? There are many images with 3000X2000 dimensions and I created a view of their content type. I also created a new image style, it is 90X70. This view displays the images in this size, but here is my question, which image size is loaded on the page load?
When you create an image style, a folder is created in /sites/default/files/styles/ that holds processed versions of your image.  When you select to use that style in views or anywhere else, only the processed image is loaded.  It wouldn't load the full size image if you have it set to the 90x70 style.