Eh, don't worry about it. Everyone's gotta start somewhere. Just take his advice aboard and try again :D. To help you find a picture (if you indeed want one), I've found the digital art section of DeviantArt tends to be pretty good for finding pictures. Just type something like "sci-fi soldier portrait", and you'll be tripping over stuff to use.

EDIT: 
[url=http://pre07.deviantart.net/9bd1/th/pre/i/2016/221/a/3/heavy_riot_police_by_asahisuperdry-dadanen.jpg]Here's one I've found already.[/url] Don't gotta use it if you don't want to, of course.

[url=http://www.deviantart.com/browse/all/digitalart/?q=sci-fi+soldier]Here's even more.[/url]