image edit was working but now not

Version 2.0.1.1
basic problem
I click the default image and click the pen
I briefly see a loading icon then nothing

what led up to the problem
this was working
I am very new to opencart and I am playing watching videos and hopefully learning
I added a couple of products and when I can to do the first one I uploaded a few images and sorted then and no problem so far
then I tried again with another product this time when I came to select the images I decided I had far too many images of products (phones mostly) which where presumably there to show how opencart would work
I decided I didn't need these and proceeded to delete some first one at a time then 6 or more at a time
after sucessfully deleting about 20 product pictures I could no longer delete edit or upload any new pictures and that's were I am now - stuck - please help

Hi HISAT,

Are you placing your images in folders. Too many images in one folder will cause issues.
How many images do you have in the image location?