Stalled Uploads

I regularly have image or file uploads that seem to stall…the blue progress bar gets close to finishing but never does. This causes a huge problem when users are uploading more than one file or image on one workflow event.

What I have set up is a product add and to help make it “faster” I have not saved the images until the user has finished cropping and editing the image using the croppie plugin. Then when the user presses a button to save images and continue to next portion of product add flow, all the images ( up to 13 ) are saved.

What happens is it seems to get stuck on a random “original image” as in my file manager I can see all the cropped images are saved but the original images only have 2 or 3 of the total possible.

What is difficult to deal with this is that I have no understanding of how to “abort” or otherwise notify a user that the app is unable to handle their request ( ie: to upload an image that is less than 2MB )

Does anybody have any experience with how to get multiple images upload simultaneously without having a random one stop the entire process? Is there any way to isolate which image is the cause to notify the user to try loading that file again?

Makes for a terrible user experience as after 15 minutes of waiting the progress never completed since it was just stuck on one image.