Got an Android phone with a cracked screen? Can't unlock the phone to download your photos and other data? If the display still works, but the touch screen won't respond, then this may be the video that solves your problem! (If your screen is completely dead, read below.)
Since I posted this video, I've learned that connecting a USB mouse won't work on every model of Android device. Some Android devices are able to act as a USB host in order to work with a mouse, and some aren't. The user's manual for your device may tell you whether or not this solution will work for you.
If your screen is more seriously wrecked so that it stays completely black when your device is turned on, then there's another solution that might help. Get yourself a multi-functional HDMI connection kit (available on Amazon), connect that to your device's USB port, connect an HDMI cable to the kit, connect the other end of the HDMI cable to a TV or monitor, and then you should be able to see what would normally be on your device's screen on the TV. Several people have said in the comments that this worked for them.
Here's a link to a webpage that describes these methods and more. (I have no connection with the author or the website.)
For those of you with more complicated technical questions, I apologize for not being more of a technical expert. I'm just a guy who discovered a cool way to retrieve my files from my broken phone and wanted to share it with other people in the same situation.
Good luck to you!