asked the GPT to do a comparison of my body from a pic taken in January of this year to one taken in September
Thanks for sending both photos — here’s a clear breakdown of the visible differences between the January (first photo) and September (second photo) shots:

Overall Midsection
Your stomach is noticeably flatter and tighter in the September photo.
The lower belly, which had more roundness in January, looks significantly reduced.
There’s more visible ab definition, especially around the oblique/side area.

Chest
Your chest appears firmer and more lifted.
The line between the pecs is slightly more pronounced, suggesting improved muscle tone.

Arms & Shoulders
Your arms look more defined, particularly through the triceps and the shoulder-to-arm transition.
There’s improved vascularity and muscle separation, which usually means lower body fat plus more muscle.

Waistline
Your waist is clearly slimmer in the September photo.
The difference in how the waistband sits shows reduced midsection volume.

Overall Impression
You’ve leaned out noticeably — not just in fat loss but in muscle tone.
This looks like a successful recomp: less fat + more visible muscle.
If you'd like, I can also break down:
What specifically contributed to those changes (training, diet, consistency)
What your next 8–12 weeks could look like
How to maintain or push further depending on your goals