The simplest way to do it without complications is with AirDroid. Install AirDroid on the Bluestacks and start it, then switch to your normal desktop and start the favorite browser. Put in the IP and the port displayed in AirDroid and accept the connection, then click on Photos, and you will have the possibility to extract the photos using AirDroid.
Install AirDroid: https://play.google.com/store/apps/details?id=com.sand.airdroid&hl=en
Or you could install Dropbox on Bluestacks, login with your account, add the pictures, then login on the normal desktop through the application or the browser.