Why is my burn so big and how can I create a smaller ISO?

[muti007]

Hey guys, I just used ImgBurn for the first time, and it created a 7.2gb ISO from a regular DVD. Why so big? How can I get it down to under 4.7gb?

 

Thanks in advance.

[Cynthia]

Sounds as you created from a double layer disc.

 

What's in the ISO? Data files/Video?