For clarification on the sometimes muddy issue of image resolution for PowerPoint presentations, Microsoft has a good explanation on their website.

In short, the resolution of your images will only display as large as the projector’s (and your computer’s) capabilities. The standard size for projection output typically has been 1024×768 at 96 dpi, but this is changing as technology changes. The new Christie projectors that we have just installed in Moffitt have an output resolution as high as 1920×1080. However, if your computer is only capable of projecting at 1024×768, it defaults to this as an output if you have the monitor mirroring setting enabled.

For more information on the Christie DHD800 projector specifications, see their website. You may also view information on the new Panasonic projectors here.