The costume pane ("backdrop pane" in the stage) is part of Scratch's built-in paint editor. The pane consists of all the costumes of the currently selected sprite. It is scrollable and highlights purple the costume that is currently being displayed on the paint editor canvas.
Uses
Without the costume pane, there would be no possible way to access the different costumes of a particular sprite. It is a necessary feature to Scratch. It also displays the costume # value of each individual costume in a sprite. By showing the costume #, one can relate what costumes are needed when programming in accordance with the costume # block.
The pane also provides, at the very top, four buttons for creating a new costume. Without these options, creating a new costume would be a more difficult process involving duplication or the backpack.
Layout
The costumes are placed vertically in the costume pane. One can scroll down or up if there are too many costumes to all be displayed simultaneously. The layout consists of the thumbnails of each costume along with a few properties. Underneath the costume thumbnail is the costume name and resolution. In the top-left of the thumbnail is a small digit representing the costume's costume # value.
If a costume is selected, it will have a purple box around it. Then, the costume will be displayed on in the Paint Editor for editing. At the top-right of the purple box is a small "x"; when clicked, the current costume will be deleted. Any costume accidentally deleted can always be undone with Edit > Restore Costume.
At the bottom of the costume pane is a menu which appears by hovering over the purple cat icon. There are four options for creating a new costume (in order top to bottom): Upload Costume, Surprise, Paint, and Choose a Costume.
Tips
.The costume order can be switched around by clicking and dragging a sprite up or down the costume pane.
.Dragging the costume into another sprite in the Menu puts a duplicate of it in that sprite’s costume pane.
.By right-clicking a costume, a small dropdown menu will appear with 3 options:
1) Duplicate the sprite (useful for animators)
2) Export the sprite (exports as a .svg file)
3) Delete the sprite (though this can be done by pressing the ‘x’ in the top right of the selected sprite)
