adding image to blender

last time my pc is on IT service I’m using a(mum told me to don’t install anything)laptop.Now I discovered online version of blender on rollApp support.I’m wondering how can I add image in background like in normal blender in rollApp online mode?

Never used it myself, but it looks like it integrates with dropbox, google drve, onedrive and a few other services.

we need to test it how import reference image,but you first.