Client side image resize slow in Chrome

[taotoo]

I'm uploading 8 images simultaneously, averaging about 4mb each, with dimensions between 3,000 and 6,000 pixels.

They're being downsized to four different variations, including the default variation.

Php 7.0 in Xammp, and 7.2 on server (the issue is present in both environments).

Edge takes 42 seconds to do this.
Firefox takes 35 seconds.
Safari (in a virtual machine) 1 minute 8 seconds.
Chrome takes over 5 minutes, sometimes while having to click through Chrome "page unresponsive" messages. I've disabled all Chrome extensions.

Chrome dev tools: