edit: This issue is resolved with the latest update. It adds a toggle below the image, with alt-text default to off.
Below is the original post context:
How can I stop alt-text from showing over images? Is there a setting I'm not noticing?
Example: 
Hey there! To completely disable the bottom navigation pill, you'll also have to turn off comment navigator in the settings. Here's a quick link to that setting: Thunder Setting: General > Comments > Enable Comment Navigation
Let me know if that disables the bottom pill completely!