jojojomarseille said over 2 years ago on Cropping Active Storage Uploads :
Hello, first of all, thanks for your videos and your work on this site.

I tried implement cropper js on my project (ROR, with active directory and direct upload, the same way as your video #279 and #280) and its working perfectly in development environment, in local, but impossible to make it works en production on heroku. 

After few days struggling, i decided, isolating the issue and try to reproduce and solve the error on a more simple case, so i tried with the source code you provide, i puted on heroku on a free dyno and its the same. its work perfectly in local but not in production on heroku.
The error i have is when i upload picture, it appear a preview directly (so blob and active directory direct upload works well) and instead of crop area with checkerboard background, i have the uploaded picture in big and in double. You can check here

I dont have any error in the console, all the http request are passing, i checked the js (puting console.log everywhere in the js and using debug mode) and all the js looks to work, cropper js seem to be there as i see it in the  debug mode. 

Its look a bit like if cropperjs didnt initialize. 
I dont think its my code because it work well in local. Maybe something to set in heroku, maybe config issue with environments. i checked all of this but without success
If you have any idea of something i could check, something to read, or if you ever made a crop function work on heroku i would really appreciate your comment.  

Thanks, wish you a good day