Here is how the story really goes:
Bitmap images, like any photograph used in a PowerPoint presentation must be measured in pixels. Not in dpi. Screen resolutions and sizes vary a great deal and there is not one unique standard size/resolution to measure dpi against.
[This was possible at the time of the original Mac (all Mac screens were set
at 72 dpi) 1984, but not anymore today].
So what you do today is to measure the image in pixels:
800x600. That is the resolution you really have. That very number of pixels. It is called "screen resolution" and it is the true and only resolution of that image until it is on your screen or projector.
If you print it, at a specified dimension you CAN set a specific DPI (with
due restrictions and limits) but you can't do so while the image is displayed on a screen. It is just nonsense.
So, to go back to the original question:
How do I increase the resolution of a PowerPoint image?
- If you have the original image separate from the PPT file, open the image in any image editing program (Irfanview.com) and increase its resolution/size. That's all.
- If the image is embedded in PowerPoint do this:
- Try first to increase the visual size of the image inside PowerPoint, as who originally placed it there may have reduced its size. In PowerPoint, just use the control handles around the select image to do so.
- Copy and paste the selected image in an image editing program and do what pointed out at point 1.
Alternatively,
take a screenshot of the image in PowerPoint as you see it (Snagit -
www.techsmith.com) and then open up the image inside any image editor as indicated at point 1. There choose the Image resizing command and increase the resolution while keeping the highest quality settings available for that operation.
(The program you use to do this makes an ENORMOUS DIFFERENCE. SnagIt is not recommended, IrfanView is acceptable, Photoshop is the best).
What is now a larger sized image is indeed by all standards a HIGHER
RESOLUTION image. You can in fact reduce its printing or display size in PowerPoint or elsewhere and obtain a higher density of pixels (dpi) as a consequence.
Since the extra resolution was added artificially you may not notice the
same benefits that are typical of higher resolution images (increased focus
and detail).
Note: You can't resize or increase the resolution of an image indefinitely. Generally you can get away with a 10-20% resolution increase without too much visible degradation of the image.
To compensate the natural and "to-be-expected" loss of focus apparently affecting images to which you have increased the screen resolution, use a free tool from Mediachance called DCEnhance. It does the magic you need. You
won't believe it.
Alternatively you may want to consider another outstanding tool that has
been designed exclusively to increase image screen and print resolution:
http://www.trulyphotomagic.com/
I hope this helps.
