WHERE TO SET CUSTOM VIEW SIZES

Although you can choose Custom Thumbnail Size from the File Browser's View menu, that custom size is set by Adobe to 256 pixels. But if it says "custom," surely you have to be able to customize it, right? Right! Just go under the File Browser's Edit menu and choose Preferences. When the Preferences dialog appears, you'll see a field for Custom Thumbnail Size. Highlight this field, enter your new default size, and click OK. Now when you choose Custom Thumbnail Size from the View menu, it will use your size (rather than the old default).