When an image gallery is created, you are shown a blank folder in which you are able to upload images into by either dragging and dropping images into the gallery or by clicking the upload button.
In addition, you are able to swap to a view which shows the following option about the image:
Name: This gives the name of the image.
Picture Size: This gives the dimensions of the image.
File Size: This gives the file size of the image.
Modified: This gives the time that the image was last modified.
When you drag the Contacts List block onto the page you will be prompted with a dialogue box with the following fields:
List Name: This field gives a name to the list. When the list has been created, this will the name that will be assigned to the list.
Description: In this field, you will have the ability to put in a description of the list.
In addition, when opening the custom list, if you click on the custom code tab, you will be able to add in extra columns or features if the you have powershell knowledge.