After saving an image through the share dialog the app throws me to the launcher, not the last app.
That's the framework's problem.
It is difficult to find another app that does more or less the same thing, but Google's Photos has an upload feature that goes back to the original app, so it is not a problem in the framework.
Prove it is the framework.
Because it's behaviour is different for different device vendors.
It is Android, that argument doesn't really make sense.
Hence we can't possibly program for every device vendor out there.
There's nothing we can do if a vendor decides to override finish callback to redirect to their launcher instead of the last app opened.
"Their" launcher, I'm using FlickLauncher? I don't think anyone is overriding the finish().
I can't seem to reproduce this in 8.1 on either Pixel Launcher or FlickLauncher on the master branch.
Is there a specific app being used? Launching in to save through Edge or Chrome returns me back to those apps when I save in Amaze.
Will test with Chrome tomorrow.
Tested, the issue seems to be of Firefox. With Chrome this issue doesn't exist.