They can be made in Photoshop or Paintshop Pro as well as really any other application that can export transparent PNGs.
I wrote a tutorial for Photoshop:
https://www.feldoncentral.com/Sachs/malogo/guide/
If you post your artwork here in an attachment, I might have time to convert it for you. Just click "Quote" to bring up the advanced editor, scroll down to Attachments, click Manage Attachments, and pick your graphic(s) there.