Either option is equally valuable depending on your current needs and lifestyle.
Remember, just because its a â€œdatingâ€ site doesnt mean to cant meet really great friends here as well.
Yes an all revealing, pouting perfect pic will get you lots of attention (not all good) just as an average photo of you in front of the mirror could cause a lack of interest.
Make sure the picture is natural and true to who you are, after all, you want a guy who is interested in the real you don't you?
Anyway, age gaps are SO in at the moment, think Harry Styles, Mary Kate Olsen and Madonna for instance.