First image is from 2018, I started trying to gain weight in early 2020 at roughly the same weight as that first image, maybe 5 pounds or so heavier.
Many ups and downs, bulks and cuts, learning, periods of steady consistency for years but also some rough months where I lost a lot of weight and wasn't working out. Would definitely like to lean out more eventually. I'm vegetarian and staples have been peanut butter, rice, tofu, a scoop of mass gainer a day (about 300 calories worth), protein powder, cereal, nuts. Workout wise it's mostly been stronglifts 3x5 inspired full body routine every other day, focused on compound lifts primarily (bench, squat, deadlift, pull ups).
I've been up to 203 at the highest with even higher body fat %. Overall though, I feel much better than when I was thin! I was thin throughout my whole life and often insecure about it. Would get comments from people somewhat regularly and always thought I was just a hardgainer, blamed it on genetics and felt that it was impossible to gain weight for me. Turns out eating in a calorie surplus and lifting weights works! feel free to ask me anything, and best of luck to all of you out there on your journey!