There are two types of CentOS installation files (32-bit and +64-bit). Each type has different versions that can be downloaded to suit customers with different needs.
CentOs 7 download address: http://www.centos.org/download/
Three image file iso downloads are provided on the Centos official website: DVD/ISO/Everything ISO/Minimal ISO
File description 
1. Click DVD ISO to download the CentOs 7 DVD ISO image file
2. Click the Everything iso button to enter the CentOs 7 Everything ISO image file. This page provides download links for a series of ISO image files for Actual County ("actual country") and Nearby Counties ("nearby countries").
3. Click the Minimal ISO button to download the CentOs 7 Minimal ISO image file
In fact, you can also click “via Toorent” on the official website to enter the download page