I noticed your comment at the end of the article that the macro only functions for the active sheet. You can easily add a second macro that resizes all the charts in all the sheets of the current workbook. Here's an example:

Sub ResizeAllCharts()
'Make all charts in the workbook a uniform size.
Dim ChtObj As ChartObject
Dim WkSht As Worksheet

For Each WkSht In ActiveWorkbook.Worksheets
For Each ChtObj In WkSht.ChartObjects
ChtObj.Height = Application.InchesToPoints(2)
ChtObj.Width = Application.InchesToPoints(4)
Next
Next
End Sub

Insert both macros. Then if you want to resize the charts on a single sheet, use the ResizeCharts() macro, and to resize all the charts in the workbook, use ResizeAllCharts().