How to Reduce the MBs in a PowerPoint
There are three main elements that increase the number of megabytes in a PowerPoint file: pictures, media and fonts. Using tools within PowerPoint you can compress pictures and media to take up less space, but the overall quality of the images will be reduced. If you know that the person to whom you're sending the PowerPoint file has all the fonts, you can remove embedded fonts to reduce the size of the file. If media is too large, even in its compressed format, you can always link to it and then use an active Internet connection when you give the presentation.
Launch PowerPoint and open the file you want to reduce in size. Click on the "File" tab, select "Info," then "Media Size and Performance." Click "Compress Media" and then choose one of the compression options. Presentation Quality will provide some compression but keep the quality high. Internet Quality will use more aggressive compression but still maintain good quality. Low Quality will make the PowerPoint file as small as possible. The compression window appears and shows the progress on compression. It disappears once the compression is done.
Compress pictures in your PowerPoint presentation by selecting the image, clicking on the "Picture Tools: Format" tab and clicking "Compress Picture." If you choose you can apply the compression to all the pictures in the presentation or just the one you selected. Compression will delete parts of the picture that have been cropped and compress the images to the resolution set for the presentation. By default the resolution is 220dpi, but you can set the resolution to be lower, which would result in a higher rate of compression and a smaller PowerPoint file.
Click on the "File" tab and select "Save As." In the dialog box that appears, click "Tools," then "Save Options." Click "Save" in the list on the left and then remove the check next to "Embed Fonts in the File." This will remove the font from the PowerPoint file and save space, but it will require the person receiving the file to have that font installed or PowerPoint will display a default font in place of the one you used. If you use "Embed Only the Characters Used in The Presentation" you can reduce the size of the file but still preserve the appearance of the presentation.
Insert videos as a link to an online video rather than embedding them in the presentation to save space. Click the "Insert" tab, click "Video" and choose "Online Video." You can paste a link to an online video into the dialog box to insert it into your PowerPoint presentation without adding to the overall size of the file. You must have an active Internet connection during your presentation to show online videos.