By default, the ImageSize property is 16 (pixels). The ImageSize property specifies the size of icons being loaded using the Images method. The control's Images collection is cleared if the ImageSize property is changed, so it is recommended to set the ImageSize property before calling the Images method. The ImageSize property defines the size (width/height) of the icons within the control's Images collection. For instance, if the ICO file to load includes different types the one closest with the size specified by ImageSize property is loaded by Images method. The ImageSize property does NOT change the height for the control's font.

The ImageSize property defines the size to display the following UI elements:

• any icon that a cell or column displays ( <img>number</img> ex-html tag, CellImage, CellImages )
• check-box or radio-buttons ( CellHasCheckBox, CellHasRadioButton )
• header's sorting or drop down-filter glyphs