Want to change the size of your thumbnail preview in your Layers, Channels, or Paths palettes in Photoshop? Hold the Control key (PC: Right-click) and click in an open area of the palette (such as the space under your Background layer or beneath the bottom channel in the Channels palette), and a pop-up menu of thumbnail sizes will appear. For instance, in the Layers palette you can choose from No, Small, Medium, or Large Thumbnails instantly changing your thumbnail view.