HI Uwe
Thank you so much for your reply. You are right, but seems we need to modifed the source code of PngComponents. The way is replace pngImage with vcl.Imaging.pngImage. In this way, we can complie the pngComponent successful. But seems the system component, TSpeedButton still can use bmp format, I don't know, why Delphi not suport TSpeedButton use PNG directly, you know, it's already contain VCL.imaging.pngImage internally. Anyway, it works, so thank you so much.