Convert bmp to png Online: bmp2png

You can use Tom's Editor to easily convert images from
Microsoft Windows bitmap .BMP to Portable Network Graphics .PNG.
Tom's Editor is a free, online image manipulation and converter program.

Go to Tom's Editor

BMP

Format created by Microsoft for their Windows and OS/2 operating systems. Images can be compressed or not.

PNG

Portable Network Graphics is an image format with extension PNG.