Windows 8.1 RTM (x86)
MICROSOFT.WINDOWS.8.1.RTM.X86.ENGLISH.DVD-WZT
RELEASE DATE: 08/21/2013
BUILD: 6.3.9600.16384.WINBLUE_RTM.130821-1623
FILE: Windows_8.1_EN-US_x86.ISO
SIZE: 2,915,131,392 byte
SHA-1: 802CFCD3A411D99C097EA7E747F0B6697F9BDAC4
MD5: 7DD36FEA0D004ACFEDBDB3A5521EF5FF

Windows 8.1 RTM (x64)
MICROSOFT.WINDOWS.8.1.RTM.X64.ENGLISH.DVD-WZT
RELEASE DATE: 08/21/2013
BUILD: 6.3.9600.16384.WINBLUE_RTM.130821-1623
FILE: Windows_8.1_EN-US_x64.ISO
SIZE: 3,899,295,744 byte
SHA-1: BC2F7FF5C91C9F0F8676E39E703085C65072139B
MD5: F104B78019E86E74B149AE5E510F7BE9

NOTE: This is the original Microsoft image.

Keys to Install:
Core=334NH-RXG76-64THK-C7CKG-D3VPT
Professional=XHQ8N-C3MCJ-RQXB6-WCHYG-C9WKB