Here is one way you could do this.
Select all of the charts to be displayed and select Copy
In an unused area of the worksheet - Paste
All charts are now present as linked copies.
Resize the charts. (Hold down the control key and click each chart in turn - then right-click the group and select 'Format object' and resize them, and in the Properties tab select 'Don't move or size with cells).
Now martial your miniatures into the appropriate shape for a slide.
Make a selection of cells that just exceeds the area taken up by your miniature charts - you can adjust the outer columns and rows to get an even border.
Copy the selection of cells (not the charts themselves).
Go to PP and select the slide to hold the charts.
Select Paste Special... and 'Paste Link' then OK
The group of charts are now on one slide and still linked to the original data.
PS chart is the same thing as graph - it's just a North American thing!