Hello!
“Bad Image” is an error from Microsoft that indicates a file is corrupted or the process of running it was interrupted by something. It is not an issue with the trainer itself.
Why they call this a “bad image” instead of just saying “file corrupted or interrupted”, no idea, your guess is as good as mine. Microsoft, right? 
- For the interruption part, your antivirus is probably blocking WeMod or the game.
- For the corruption part, something probably went wrong during installation.
- Try the steps in this post: I can’t Install WeMod / "There was a error installing the application" - #2 by Ravenfyre. The thread title is different to your issue, but the steps are the same.
- And verify the integrity of the game files via the game launcher.