An ISO file contains a full image of a CD or DVD disc; these files can become very large depending on the amount of data that the source disc contains. In some cases you may want to split an ISO into multiple parts so that the file size is more easily manageable and portable. You can use the PowerISO application to split an ISO image into multiple volumes of any size you want.
Run the PowerISO application.
Hold the CTRL key and press O to open an "Open" dialogue window.
Navigate to the folder that contains your ISO file and double-click the file to open it.
Click "File" in the menu bar, and then click "Image Properties".
Click the "Advanced" tab.
Check the "Split to multiple volumes" in the upper-left of the dialogue window.
Select the size that you would like to make each volume of your ISO file from the "Volume size" drop-down menu.
Check the "Enable password" protection box and type in a password if you want to password-protect the archive.