You can rename items directly in the Gallery. The method changes depending on what you are renaming.

Rename a Drawing

Tap the name located below the drawing thumbnail in the Gallery.

Rename a Folder

Tap the folder's name at the top of the Gallery screen.

Rename a Folder in the Sidebar

Use Tap+Hold on the folder name in the sidebar. A simple tap opens the folder instead.

Rename a Subfolder

Use Tap+Hold on the subfolder name. A simple tap will show or hide its contents.