Questions and postings pertaining to the development of ImageMagick, feature enhancements, and ImageMagick internals. ImageMagick source code and algorithms are discussed here. Usage questions which are too arcane for the normal user list should also be posted here.
I tried "-background None" before, but my image viewer software display white color instead of transparent, so I thought my command is wrong.
When I used another software, it works. Thank for your help, snibgo.
Yes, some viewers show transparent as white, so it can be confusing.
When I write a command, I often use "-background pink" or blue or something, so I can clearly see what I am doing. When it works, I change it to "-background none".