Neither... both a mirror and photograph vary depending on the lighting conditions and position. A mirror is more likely to be in a fixed position which is the reason why you don't always look the same in every mirror. Vice versa with a picture, it depends on what angle and where it was taken.
A Video is the best representative of how you look
The mirror. Pictures are a one dimensional view of yourself without giving any other detail than from what the distorted capture device took.
On a side note, makeup, to me that's a no-no. Be yourself, you probably look 100times better without it. On top of that it's deceitful, you want someone who will fall in love with you for you, not for some fake image you're trying to protray, be yourself, that's all I can give you.
Reflection in a mirror. The mirror is reflecting the light back and is being recieved by 2 eyes from a little different angles just as eyes see a person. A camera only has 1 eye and as such sees things a little different.
Reflection. At least you can see multiple facets and angles of yourself - pictures are limited in that sense. Either way light and reflection will affect your appearance, but as Anonymous4Ever mentioned, it's better with mirrors.