Hi padchadayni ,
You only need to add the margin to create space in between the buttons.
Your CSS should end up looking like this:
/* Change the margin-top to add space */
.buttonizer-button {
margin-top: 30px !important;
}
/* Change the width to increase the image size */
.buttonizer-button img {
width: 80px !important;
}
Increase the margin-top to add more space in between the buttons.

You can also futher increase the size of the image by increasing the width.
If you increase the width, you will also have to increase the margin-top to create spacing again.