if you want to copy files to your apps, paste your images here. C:\ProgramData\BlueStacks\UserData\SharedFolder
if you want media from your apps then install a filemanager on bluestack using it and copy files then Navigate to /sdcard/bstfolder/bstSharedFolder/ and paste the files. This file can now be accessed on the PC by navigating to C:/ProgramData/BlueStacks/UserData/SharedFolder.