For what it's worth: I deleted a bunch of pics from my phone, only to realize many months later I wish I hadn't. I have an app (called File Transfer Pro) and I use it to transfer files (usually photos and videos) from my phone to my computer. So one day i was transferring pic files and noticed that those pics had deleted months ago showed up on File Transfer Pro. I was able to download them.
Anyways, what probably happens is Android merely marks the file deleted in the FAT table, just like MS-DOS did. The data is still there. No special software to install on your computer either. File Transfer Pro starts a web server on your phone. You point your favorite browser to the address it says to point to.
Note that the phone and your computer need to be attached to the same WiFi network for this to work. And the web server it creates uses standard HTTP, so you should only use the app on a trusted WiFi network.