PPT files are usually too large because too many pictures are put in. If this is the reason, it can be solved by the "compressed picture" function that comes with office.

Take office20 10 as an example. First, select a picture and select "Compress Picture" from the picture toolbar, as shown in the figure.

If it is determined that the entire PPT picture does not need to be edited, you can uncheck "Apply to this picture only", select other as needed, and then confirm to compress the document.

For reference only.