And if terminal listings aren't forthcoming... the "fix" is probably a simple matter of getting a program such as GraphicConverter to add the missing preview —by using its browser view, and then choosing “Create preview” from the action menu. [though i suspect the graphics proggie originally used to save those files may have a similar feature (a matter of rtfm)... and, assuming those files contain any data at all that is [as we have no info about their actual size.]