Transferring iphone pictures to sd card?

So i recently went to a concert and i wanted to put the pictures/videos on an sd card. I have over 5000 photos in my camera roll so instead of importing ther few videos to my computer i just plugged in my phone, inserted the sd card and copied/pasted (on the computer is says move to new location but same thing) the photos by having two libraries open. I need to clear up space on my phone and id like to know if the photos are actually on the sd card, since i just copied and pasted them. Please help because i barely have any storage on my phone and i would be devastated if i lost all my concert videos

If the files are showing up in the window of the SD card and you can open them from that device then they are on the SD card and you are good to go

First thing, make sure you keep a backup of the pictures on your computer, 2 locations are better than 1 to backup to.

open the folder for the SD card in the 'Computer' folder (if your in windows) and see if the pictures are there and open a few to make sure they are not corrupt.

what i usually do is this:

open the folder on the phone with the pictures.

open a second folder with the pictures you copied over.

highlight all (or the folder) and right click on them, select 'proporties' (do this for each)

make sure the file count is the same for each and the size is the same for each (size might be different, and file count may be different give or take 1 or 2 files)

if they both match then you have all the pictures off.