The highest resolution supported by the Optoma HD25 is 1920 x 1200 (WUXGA). That's over seven times the resolution of the most frequently found graphics resolution of 640 x 480 (VGA).
This data projector's resolution (1920 x 1200 (WUXGA)) is actually the best supported resolution across all projectors that have been around for more than two years.
A 640 x 480 (VGA) graphics resolution is the worst supported resolution amongst comparable types of data projector.
If the resolution of this projector is too low for you then you might want to consider the Acer H9500BD (1600 x 1200 (UXGA and cheaper)|1920 x 1080 (HD 1080 and cheaper) and cheaper).