I've had a similar experience where a couple contracted me to handle their anniversary sound production using their first dance song. I picked Audacity, powered the MP3, zoomed straight into the chorus, and exported a crisp black and white waveform, which is at 600 DPI. Worked on it over time and gave it to them. I can still recall the joy on their faces when they played it.
One thing that I like about Audacity is that it is free and can do this job perfectly without any issues. You just have to trim the chorus, play file, click on export as picture and then pick PNG. I don't need any plugins for that.
You can also scale the PNG to any size you desire using vectors. I can help you handle this if you need my services. Thank you.