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Information Site References - for more detailed
information
One of
the most common complaints about PowerPoint is the size of the completed
presentation. A presentation can go from being 1 MB to 10 MB after the
addition of a few graphics.
Here are a few things to consider to reduce the file size of your presentation.
Monitor Resolution
If your computer (or projector) is running at a resolution of 1024
pixels wide x 768 pixels tall, then there is no point having any images
with more pixels than this.
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If the image to be displayed is full screen, i.e. occupying the
whole page area in PowerPoint, then aim for about 1000 pixels wide.
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If the image will occupy half the width of the screen then halve
it. e.g. aim for about 500 pixels wide.
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If the image is portrait e.g. it's taller than it is wider, then
aim for an image that is about 750 pixels tall, or for a half size image
about 375 pixels tall.
If your computer is set to a different resolution:
Adjust these sizes if the image will appear smaller in the
PowerPoint show.
Reducing the Pixels:
To resize your bitmap pictures use your favourite graphics software
such as Photoshop or PaintshopPro.
Save the file in the required graphic file format. If PNG is
available choose this format as it is the best for PowerPoint.
Graphic File Formats
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.PNG - Portable Network Graphic
One of the best
formats for PowerPoint |
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Does not lose any information
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Works with all the different numbers of colours (256, 16 bit, 24
bit, grayscale)
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A Compressed file (smaller file size, especially 256 colour files)
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Widely compatible
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Takes very little time to decompress in PowerPoint
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.JPG - Joint Photographic Expert Group
This format is OK
for PowerPoint but better for email and websites. |
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Loses information.
But you do have control when you save it how much information is
lost
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Only works with 24 bit colours (16 million)
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A highly compressed file (very small files)
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Widely compatible
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Takes longer to decompress in PowerPoint than .PNGs
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Also puts a higher load onto the processor to decompress
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.BMP - Windows Bitmap
This format is OK for PowerPoint
but the file size is very big in comparison to PNG. |
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Does not lose any information
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Works with all the different number of colours
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Can be compressed but not 24 bit colours.
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Very BIG files
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Widely compatible
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Very fast to load and display in PowerPoint
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.GIF - Graphics Interchange Format
This format is OK
for PowerPoint but better for email and websites. |
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Loses information as it can only have a maximum of 256 colors
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Only works with 256 colors
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Compressed format
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Widely compatible
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Does not take anytime to decompress as it is not compressed
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Digital Cameras
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Most cameras have a setting for resolution.
Some common ones are
640x480, 800x600, 1024x768, 1280x960, 2048x1536
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Some cameras have a quality setting, this is normally just how much
.JPG "compression" to apply. Generally, the more compression, the more
information is lost with .JPG files.
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Think pixels. Set it to 1024x768 as this is the closest to what you
computer is set to.
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If you are going to be cropping the images or you cannot get close
enough to the subject when you take the picture, then set the resolution
to something higher, so you can still crop the image but still end up
with enough pixels.
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Copy the images to your computer
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Save it as a .PNG
Scanning
On most scanning software there is normally an option called
resolution or Dots Per Inch/DPI.
Before you scan it you need to adjust the Resolution
or DPI.
If for example your original image on the scanner is 5 inches
(12.7 cm) wide and the image needs to be about 1000 pixels wide.
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If the scanner is set to scan at 300 DPI the bitmap image will end
up 1500 pixels wide. Too large for our PowerPoint slide.
( 5 x 300 = 1500)
(Physical size x DPI = pixels)
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Set the scanner at 200 DPI.
So for every inch it will end up with 200 pixels.
(5 x 200 = 1000)
 It's always better to scan the image at the correct pixel size in
the first place, as re-sizing the image (especially bigger) will produce
bad results.
Save it as a .PNG
Colour
See what your computer is set to, then make your images the same.
So if your computer is set to 16 bit colour (the most common
setting). Then reduce the number of colours in your images to the same
number of colours. As you will not gain any quality advantage by having
more colours in your images than the computer or projector can display.
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No
of
colours |
Name |
Comments |
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16 |
4 bit |
Don't even go there |
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256 |
8 bit |
Awful for PowerPoint, most old laptops will be set to 256 colours |
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65536 |
16 bit or Hi-Colour |
Probably the optimum setting for PowerPoint presentations |
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16 million |
24 bit or True Color |
Overkill - Looks great but it willl slows things down |
Making a large presentation smaller
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Open the presentation.
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From the View menu select Slide View.
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Press the PageDown (PgDn) key to advance through the presentation
one slide at a time.
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f you
notice one particular bitmap/picture/image takes a fraction of a second
to display, then chances are this is the offending item.
It has got TOO MANY PIXELS in it.
To make doubly sure this is the offending item:
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Display the picture toolbar and click on the Reset button
 to reset the bitmap
to its original size.
If the bitmap is guilty it will reveal itself by growing to an enormous
size, most probably off the page!
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First of all you need to get that image out of PowerPoint at the
best quality, before we reduce the number of pixels in it.
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Select the image
Copy it to the clipboard
Load up
Microsoft Photo Editor
From the Edit menu select Paste
Save it as a .PNG
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Load up a graphics software, Photoshop, PaintShop pro
etc.
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Open the bitmap you saved using MS Photo Editor.
Select the menu that displays how many pixels the image contains (info,
image size etc)
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You will probably find that it contains lots and lots of pixels. ie.
more than 600
Select the menu that will change the image size (re-size, re-sample,
image size or similar)
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Change the number of pixels the correct amount.
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To make the presentation even small consider changing the bitmaps
to 256 colours
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Save it as a .PNG
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