It’s not off-topic, and it’s not something that everyone understands.
See this earlier thread.
This is what it says in the EULA on installing FontCreator:
In the case you purchased a Home Edition license for SOFTWARE, and use it to create or modify a font, you are not allowed to use that font for commercial purposes.
Regarding the comments in that thread, at first I thought “Commercial Use” meant that one could not sell the fonts made with the Home Edition, but now I see that the terms are reasonable. If you use IrfanView commercially you also need to pay for a license. The pictures are your own copyrighted works, which you may do with whatever you wish, but if you use IrfanView to manage or edit them, you are using the software commercially and need to purchase a license.