The Quick Design Picker in Gallery Designer works almost the same way is it does in Album Builder. This article reviews the best way to use QDP in Gallery Designer.
Add a Room
First, drag and drop a room onto the greyed out spread. Doing so will add another room for you to design.
Next, select the images, then drag them to the spread and drop them into the room. To select multiple images, click your first image and while holding down the Shift key, click to the last image you want to use to select everything between your first and last image. Individually select multiple images by holding down Cmd/Ctrl while selecting the images that you would like to use.
After you've used an image, you'll notice that it grays out. This allows you to distinguish between images that have already been used and images that have yet to be placed. Even though it's grayed out, you can use images more than once.
When you drag your images into the room, you will notice a shadowed preview of the auto design will pop up. You can either scroll through designs by continuing to drag on and off the room or simply drop your images onto the room and use the Quick Design Picker icon.
QDP From Planner View
To access the Quick Design Picker from Planner View, hover or click on the room in question and then click the icon with four squares. This will open the Quick Design Picker.
Quick Design Picker
You will be presented with 12 wall design options to choose from. You can rotate images through the designs by clicking the rotate images icon in the upper right hand corner.