Using a simple tool in PowerPoint makes it super easy to create a video slideshow with music. I suggest using PowerPoint for this task if you have it on your computer because the fun web-based apps usually have watermarks on them unless you upgrade. Additionally, PowerPoint on your PC doesn't require you to login to another program. It's not cloud-based so it's local to the computer but it also means you don't need to reply on the internet to create your slide show.