When you want to transfer photos from Samsung Galaxy S8/S8+ to computer then the simple way is to connect your phone to PC via USB cable and then select the photos from DCIM folder on Samsung phone, copy the photos you want and paste them in a folder in which you want them to keep.
Apart from that, you can use a professional transfer tool like
Android Transfer [androiddata-recovery.com] that can help you to transfer photos and other useful data from Samsung Galaxy S8/S8+ to computer. The tool is easy to use and transfers every photos you want to computer.