I have +- 500 .bmp's that I would like to convert to .png's. It would be especially nice if the color white (#FFFFFF) of the original BMP's could be converted to transparent in the .png's.
PNG-8 is enough since the .bmp's are 16-colors.
I would prefer a command-line tool that I can put in a batch file, but any would be useful. Do you know of such a tool?
edit: The OS I use most is Windows 7 x64, but I also have Cygwin and various linuxes available