That character could be anyone. I'll probably write several scenes with him, or her. Maybe a short story or two. Nothing that I ever plan to sell to anyone - unless it turns out to be "the one" but it will help me craft the idea into something that I can really use, a tool for my tool box. There are images like that in your life, that strike you and make you take note. You should literally take note. When you write them, you will own them.
In my early writing I thought that the image could BE the story. I was complimented on my vivid descriptions - everyone always "felt as if they were there" - but there wasn't any depth so it was like watching a John Woo movie or worse, playing a video game, or worst of all, playing a John Woo video game. I didn't get it at the time despite being given that very accurate criticism.
Now I know better. I still write shorts when an image grabs me, try to tie them into a story structure because that's really, really good exercise, but as cool as a line or image is, it's only a promise of something more.
A second child. Of course. He burst through the door into the smoke filled room, coughing, the beam of the flashlight nearly useless. Under the bed. He dove to the floor searching for any sign of the boy. A sharp pain in his stomach, the unfortunate meeting of Thomas the Tank Engine and the two egg McMuffins he'd had for breakfast. Feet. He crawled forward, reached under and pulled the limp form into his arms. Breath. The flashlight was forgotten, the doughnuts and break room banter before the call forgotten. The child was everything as he sprinted toward the light of the open window.