where do my photos get downloaded to on my pc

Did you actually download them or just sync the device to the PC? If sync'd, you won't see them. They store in an Apple format that isn't viewable. If you moved by cut/copy the files, you should be able to find them easily. Whatever your default folder is. You can do a Windows search to find them.

Depending on the version of Windows you are using, the default location for the Photo Import utility in Windows is the Photos Library, or My Pictures folder, unless you purposely changed that in settings.

Syncing the device has nothing at all to do with importing photos to your PC. This will explain what you need to do.

Import photos and videos from your iPhone, iPad, or iPod touch to your Mac or Windows PC - Apple Support