What does Fixed Image Aspect and Autosize Grid options do?

[healthyfat]

What does Fixed Image Aspect option in style property do?
What is the difference between Autosize Grid enabled and disabled?

Is there a description of all the options in style property?

[skybitscom]

Fixed Image Aspect would mean the image has a set image size of x and y pixels. An Autosize Grid would relate to resizing per a percentage number instead of a fixed number.