1. How dare he point out your fat legs!!! OMG that's awful. Bah.
2. I can totally feel your pain. My band get recorded on video quite a lot. Usually it doesn't matter too much as it's other people's wedding videos, which I never get to see, but when it's for corporate functions, or friends' gigs they always delight in showing us the videos and I usually watch in stunned silence and in horror at how large I look.
Don't stress whilst you're out shopping. Be relaxed and open-minded about what to wear and you'll find something great. I don't believe the perfect gig dress exists - I've not found one yet! But there will be many great outfits out there.
My suggestion would be to concetrate on making yourself look/feel the best you can - have a bath, face mask, exfoliate, spend ages doing your hair and make up so you feel fabulous. I'm guessing you wear all black? So that's slimming immediately! Have you got some funky jewellery you can accessorise with?
And finally - easy for me to say, but, forget about the video. You're there to perform. Get lost in the music (that sounds so cheesy but you know what I mean) and enjoy your performance, and that will come across on the video. People are there to listen/dance to you, not watch, and I bet you've got a fantastic voice. You must have to sing rock, it's hard to sing! I can't flipping do it...not powerful enough! So relax and just perform, and that way you'll come across as yourself, natural and bl00dy gorgeous.
ROCK!
x