how to selectively mass delete photos using image capture

[Appletise]

why image capture can no longer delete photos? I remember I could transfer from image capture to my external HD and then delete the highlighted photos, which would free up space on my iphone6s, now when I right click, the 'Delete' is greyed out. I read that you have to turn off your icloud for photos, so went to the iphone6s, selected, settings, icloud, photos, I unselected 'iCloud Photos' it then give me choice to 'Remove from iPhone' 'download photos & videos' l then choose 'Remove from iPhone' but then it says 3340 photos and videos will be removed from this iphone. I dont want to delete them all, l want to selectively mass delete. My 5GB icloud has already been well used up, how can l selectively mass delete? l logged into my icloud on a browser, but dont see an option to turn off icloud for photos. please help!