This is fantastic! It's clear that you've put a lot of thought and effort into creating this GIF generator, and it's great to hear that it's been a time-saver for you. The feature where it automatically detects banner dimensions and allows for quick snapshots with CTRL key or the button is very user-friendly. Plus, the option to save in multiple formats is a nice touch for flexibility.
It's understandable that the program is for Windows only due to your limitations with compiling for OSX, but hopefully, someone with Adobe Animate and a Mac can lend a hand in the future.