I am preparing a PowerPoint presentation with about 80 photographs. What is the best size and resolution for the photos to get the best result without making the file too big? Rejane Belanger
An article on the Microsoft Office site says: "The Basic Rule is this: For images that fill the slide, the image size (in pixels) should be equal to the video screen's resolution. For example, if your screen resolution is set to 1024 x 768, that's the size you want your full-slide images to be. If the image occupies only half the width and half the height of the slide, it should be 512 pixels wide, and or 384 pixels high." (http://office.microsoft.com/en-us/powerpoint/HA011163551033.aspx)
I usually start with images intended for web use, with a resolution of 72 pixels per inch, not ones designed for printing (probably 300ppi). PowerPoint seems to assume 100ppi, so resampling your high-resolution images at 96ppi -- using Irfan View or PhotoShop or whatever -- will probably produce better results.
However, try not to change too many things in PowerPoint. It has a wonderful "undo" capability, but if you change an image it will keep the old copy, just in case you want to go back to it later. This will, of course, make the file correspondingly larger.
Backchat: Robert D Heap says: "If your picture is full screen, insert it as a background. This eliminates all the edit clutter and reduces the file size considerably, with no visible loss of quality. Text can be superimposed if desired." If using more than one picture, he adds, save the whole slide as a jpeg, then use this as the background on a new blank slide: "The file size is reduced, typically by 60%, I find."
