preview.app 6.0.1 does not clear picture list when app is closed OS X 10.8.2

If you launch Preview 6.01 and within the resulting open file dialog, you specify open without selecting any file, it will automatically open any Preview compatible files it finds in the designated folder. This cannot be resolved by deleting preferences or clearing the recently opened files menu items.

Preview will not behave this way, if you specifically double-click a file from the Finder and launch Preview, choose a file from within the Preview open file dialog, or cancel the preceding dialog, which leaves Preview still open.

For your circumstances, this may require a workflow change on how you use Preview.

Do you mean that when you quit Preview it "remembers" the images that were open, so that it reopens them the next time?

This is the default behavior for apps in Lion and Mountain Lion.

This can be changed, either temporarily or definitively.

To prevent this in one occasion, hold down the option (a.k.a. "alt") key and in the File menu you'll notice that "Quit" has become "Quit and discard windows". If you choose this, Preview (and most any application, for that matter - at least those updated for Lion or ML) will discard all windows and will start fresh the next time.

To make the above the common behavior (Caveat: this will affect ALL applications):

go to System Preferences->General and check the box that says "Close windows when quitting applications".

Re-read my previous post. I wrote the default behavior of Preview and circumstances, rather clearly I thought. Something that I tested before posting.

If one holds down the Option (alt) key in the Preview File menu, you will see that “Quit” changes to “Quit and Keep Windows.” Also, in the General System Preferences, I have “Close windows when quitting an application” selected.