I am new to mojoPortal and am having difficulty managing galleries.  If I upload photos and subsequently want to remove some, but not all, of the photos, how would one best go about doing that?  Using the File Manager left me with <?> placeholders in my gallery slideshows that I can't seem to remove.  Which I guess makes for the second question, how does one convince the galleries to rebuild themselves to not have the <?> placeholders?

Thanks!