Welcome to CuteSoft support forums.
Yes. You can.
The image name of the toolbar type "table" is instable.gif.
You can just overwrite the following images using your own image:
/CuteSoft_Client/CuteEditor/Themes/Custom/Images/instable.gif
/CuteSoft_Client/CuteEditor/Themes/Office2003/Images/instable.gif
/CuteSoft_Client/CuteEditor/Themes/Office2003_BlueTheme/Images/instable.gif
/CuteSoft_Client/CuteEditor/Themes/Office2000/Images/instable.gif
/CuteSoft_Client/CuteEditor/Themes/OfficeXP/Images/instable.gif
Hope it helps.
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