Batch-convert Pictures From One Folder/format To Another?

Hi! I don't have a printer, so I have to ask others to print out for me. I have some color pictures to print out tomorrow. Now, they are in .bmp format, and the person who usually prints them out for me has a Macintosh. Is that a problem? A short while ago, I converted those pictures to .png format and saved them to a different folfer one-by-one. I'm wondering ig there's a way to batch-convert them in one shot. I'm willing and able to write a batch file to do it; I just need the right program and switches. Thank you. BTW, the pictures are mostly screenshots of some C64 games. I have some online. Do you want them?

 

https://imagemagick.org/

 

I tried the link but am a little confused: the download info implies that it is an interface for other programs, and while I have experience with coding, I don't have that much experience. The rest of the info states that it can run from a command line which is good, but how do I download that version and the GUI?

 

There may be GUIs but generally it is a command line tool - you can write a bat file to convert the files.

This tool is like FFMPEG, it is used in a lot of other programs because they are such resourceful tools.

Maybe you need this: https://file-converter.io/ (if you look on GitHub, ImageMagick is the engine they use too)
Select the files, right click, convert, then sort by extensions and copy them to a new folder.

 

Thank you. It looks better for my purposes.