The highest resolution supported by the Optoma W290 is 1600 x 1200 (UXGA). That's over six times the resolution of the most frequently found graphics resolution of 640 x 480 (VGA) (which is also supported by this Optoma projector). In addition, this projector support graphics resolutions of 1024 x 768 (XGA) and 1280 x 1024 (SXGA) and 800 x 600 (SVGA).
This data projector's resolution (1600 x 1200 (UXGA)) is in fact the best supported resolution across all 13000:1 contrast ratio projectors that have been available for a similar time to the W290.
A 640 x 480 (VGA) graphics resolution is the worst supported resolution across similar types of data projector.
It is worth considering other data projectors that support graphics resolutions of 1024 x 768 (XGA), 1280 x 1024 (SXGA), 1600 x 1200 (UXGA), 640 x 480 (VGA) and 800 x 600 (SVGA) including a higher rated product such as the Optoma DX325 (£310.14).
If the resolution of this data projector is too low for you then you might want to consider the Benq MS521 (£281.40) (800 x 600 (SVGA and higher rated),1600 x 1200 (UXGA and higher rated),640 x 480 (VGA and higher rated) and higher rated).