Transformation photos are highly problematic because success and human worth are not size-dependent, nor should happiness be. Intentional weight loss is not shown to improve health. Intentional weight loss efforts are most likely to result in weight regain.
Transformation photos typically consist of at least a pair of side-by-side photographs of a person purported to display their "progress" or "success," but which almost universally display weight loss over time. Sure, weight loss can be a kind of progress, even if that means progression through an eating disorder, physical illness, cancer, depression, or poverty. But the reasons for weight loss never seem to matter since becoming smaller is so widely viewed as a positive change.
You cannot determine health based on appearance.
In my case, any transformation photos I could post would show obvious weight gain. What they don't show is my recovery from disordered eating habits, untreated depression, over-exercising and under-fueling. Nor do they show that I've completed two half marathons, a 15-mile obstacle race, and several triathlons since I've begun running. They can't show that I've become stronger, fitter, faster, and far healthier since gaining ≈15 pounds (≈half muscle, half happiness) over the last 5 years.
Weight change does not show wellness.
It's not petty envy at being unable to effectively participate or receive feedback and admiration that fuels my irritation with transformation photos. It's frustration that body size is used as a measure of success without regard for any person's actual health or positive changes in wellness. It's the widespread belief that weigh loss is the ONLY measure of success and that without seeing numbers on a scale decrease, one can only be a failure. Even moderate weight loss is seen as a failure if one hoped to achieve more. This is the message blanketing so-called "health" and lifestyle magazines, TV ads, "inspirational" fitness memes, gym walls, and "fitness" forums.
Body size does not indicate health.
What if instead of posting weight change and body measurements with "transformation" photos, we captioned them with accomplishments such as strength increase, distance goals met, increased energy levels, lowered blood pressure, and improved emotional health? These are things more people can pursue and control, goals more inspirational than statistical outliers largely dependent on genetics and starvation-levels of caloric restriction. Actual measures of health and wellness rather than shallow and false substitutes for health.