What is the difference between CentOS "DVD" vs "Everything" ISOs
Solution 1:
CentOS sure keeps this information well hidden. Excerpts from this link:
Various installation images are available for installing CentOS. Which image you need to download depends on your installation environment. All of these images can either be burned on a DVD or dd’ed to an USB memory stick.
If you are unsure which image to use, pick the DVD image. It allows selecting which components you want to install.
Live media images are also available, both for Gnome and KDE desktop environments. These allow you to test out CentOS by booting from the DVD or USB stick. The third livecd image uses Gnome, and as the livecd name implies, it is small enough to fit on a CD. This image does not contain libreoffice. You can also install CentOS to your hard disk from the live media images, but please note that what gets installed on your hard disk is exactly the same as you see when using the live media. For more flexibility in selecting which packages you want to have installed, please use the DVD image.
The everything image contains all the packages that are available for CentOS-7, including those that are not directly installable from the installer. If you want to install those other packages, you must mount the install media on your installed system after the installation, and copy or install the packages from there. For most users installing from the DVD image and then installing the other packages with ”yum install ” instead is probably easier.
Solution 2:
The "DVD" ISO is small enough that you can burn it to a single-layer DVD (~4.7Gbyte). The rest of the software will be downloaded via the Internet if you chose to install it.
Solution 3:
Just found the answer in one of the "Readme" files
README.txt
CentOS-6.7-i386-netinstall.iso
This is the network install and rescue image. This image is designed to be burned onto a CD. You then boot your computer off the CD.
CentOS-6.7-i386-minimal.iso
The aim of this image is to install a very basic CentOS 6.7 system, with the minimum of packages needed to have a functional system. Please burn this image onto a CD and boot your computer off it. A preselected set of packages will be installed on your system. Everything else needs to be installed using yum. The set of packages installed by this image is identical to the one installed when choosing the group named "Minimal" from the full DVD image.
CentOS-6.7-i386-bin-DVD1 (2).iso
These two dvd images contain the entire base distribution. Please burn DVD1 onto a DVD and boot your computer off it. A basic install will not need DVD2. After the installation is complete, please run "yum update" in order to update your system.
CentOS-6.7-i386-LiveCD.iso
This is a CD live image of CentOS 6.7 designed to be burned onto a CD. You then boot your computer using that CD. The disk can also be used to install CentOS 6.7 onto your computer but without offering any package selection options at install time.
CentOS-6.7-i386-LiveDVD.iso
This is a DVD live image of CentOS 6.7 designed to be burned onto a DVD. You then boot your computer using that DVD. The disk can also be used to install CentOS 6.7 onto your computer but without offering any package selection options at install time.
Remember that in order to be able to partition your disk you will need to run the GUI installer which in turns needs enough RAM. The same is true for the network setup step. The release notes ( http://wiki.centos.org/Manuals/ReleaseNotes/CentOS6.7 ) provide more details about these aspects.