As shown here: 2016 SOLIDWORKS API Help - IconList Property (ICommandGroup) there are different icon resolutions. If we use only 128x128 resolution in the IconList multiple times then also its working. Then why should we use lower sizes icons (SolidWorks 2017). For SolidWorks 2016 and less the icons recommended are 16x16 (small icon list) and 24x24 (large icon list). After trying 128x128 its working fine in SolidWorks 2014. Am I going wrong? Please suggest.