The CTHD-61B supports a maximum resolution of 2560 x 1600 (WQXGA). That's over thirteen times the resolution of a 640 x 480 (VGA) projector, which is the most frequently found resolution supported by projectors of this spec and age. 640 x 480 (VGA) is also supported by this Barco data projector.
This multimedia projector's resolution (2560 x 1600 (WQXGA)) is actually the best supported resolution amongst all similar spec projectors that have been available for a comparable time to the CTHD-61B.
The worst supported resolution amongst comparable types of multimedia projector is 640 x 480 (VGA).