If you do not own the copyright to the music/song and do not have the express permission of the legal copyright holder, then yes, it is illegal. Especially if you plan to share the file.

Of course, this does not apply to material in the public domain. Or your own works (your work is somewhat protected whether you have filed with the US Copyright Office. I say "somewhat," because by officially filing you have a better chance of protecting yourself and your intellectual property, because you then have legal proof of possession.)

Same applies to logos used without express consent -- unless it is your own creation. Logos are protected by trademarks rather than copyright.

You could be setting yourself up for serious legal trouble if you wrongly use Intellectual Property owned by someone else. Does the word "theft" ring a bell?

As a songwriter and artist myself, I have the right to protect my creative property and I will. Artists work harder than many people realize and it is unfair, immoral and just plain wrong to deny the copyright/trademark owner the credit or income they are due.