Split a group of images vertically with output in different directories

I have a directory with 170 png photos on a Linux Mint machine, which I want to split in half. I came up with a solution, but it didn't work properly, because it overloaded the cache. The command I had written and has worked for 1 image was: convert -crop 50%x100% ../image_location.png image_location_cropped.png I tried to write a loop, but I wasn't successful. Something like this: ~~~ for i in Testovnica_chemia-???.png do convert -crop 50%x100% ../Testovnica_chemia-???.png Testovnica_chemia-???_upravene.png done ~~~ Error message looked like this: convert-im6.q16: cache resources exhausted `../Testovnica_chemia-056.png' @ error/cache.c/OpenPixelCache/4083. How should I modify it?