After reviewing for a half-hour, my Anki goes blank, and the screen becomes black. This issue happens when I added media to my Anki, which increase the size to 10G. How could I solve the problem? Should I delete all the media which I added?
That’s quite a lot!
Maybe your system is running out of memory, in that case, you may have to delete some media files.
If I eliminate some bulky media form collection.media folder, will they eliminate from my deck too?
Is there any way to delete their trace completely from my deck?
References to them will remain in your deck (though that should not cause a problem AFAIK).
You can edit the notes as you study them to remove these references.
Please note that shrinking your media folder will not likely change the amount of memory/RAM Anki needs. It will alter the amount of disk space your collection takes up however.