With Fire TV Stick 4K. You can calibrate the screens to avoid images, content bleeding off the screen.
If you are using Fire TV HD, it's not possible.
You may want to look at your TV settings, some TV have this setting too.
How to 'Calibrate Your Display' to Fire TV Stick 4K?
On the 'Home screen' window, look for the 'Settings' tab in the options listed on the top bar.
Under the 'Settings' tab, look for the 'Display & Sounds' option among the list that will be displayed.
In the 'Display & Sounds' option, go to the 'Display' option from the list of alternatives provided.
In the 'Display' tab, select the 'Calibrate Display' option from the two alternatives provided.
You will be taken to the calibrator screen. As mentioned, start calibrating your device display using the 'UP' and 'DOWN' buttons provided on the remote, making the arrows completely visible. Select 'Accept'.