My fiance has lost about 40 lbs and wants to lose another 25.  We're both in our 50's and I've been working on losing weight myself.  She's gone from 18/20's to 14/16's and even when she loses additional weight it is unlikely that she will get smaller than that in clothes sizes due to her build (5'9 and buxom).

I took a few pictures of her yesterday (which I think she looks pretty darn good in, and I told her that) and her only response was "Not one of my better days."  She knows that at our age weight loss can be tough. She's done well, and she's aware that she'lll never have the body she had when she was 18 again, but I just wish I could get her to see how good she looks and recognize how well she is doing.

What works for you folks? what kind of encouragement gives you the most positive feedback?

Honestly, the best thing I've EVER done for myself is joining SparkPeople.com.  If she joins that site, she can meet up with other arfcom chicks who are doing the women's competition for encouragement.  I think it's too late for her to join our competition (we're already 4 weeks into it) but she can join us for motivation as well as all the amazing tools that spark has to offer.  Oh, and if she wants to join that site and "meet up" with us on there, just send me a pm and I'll give you/her my user name.  Or you can post in the weight loss challenge thread.

My $0.02.  

a23n has a good point (although I forget who you are on SP, sorry girl
). There's also a lot of information on SparkPeople, it's free and she could also find a group of older folks. The information from an external source, no offense but sometimes when it's our fella saying something would just get obstinate, could help her accept who she is right now.

I know about the buying bigger sizes just so they'll cover your legs and it stinks! It can also keep her from feeling like she's making progress. Does she enjoy wearing skirts? Maybe compliment her when she wears them and maybe she'll gravitate to those more. I find I can get away with smaller sizes in most modest styles of skirt.

As to the pictures, they're brutal.
I have recently seen that the camera is a very unforgiving eye. I've known some who don't know how to accept a compliment but she is hearing you. Keep them up but not to the point of sounding fake.

Keep the picture that she responded negatively to and if she loses more weight you might show her that and tell her how far she's come from the body she didn't want anymore.  

Just my suggestions. I have no idea if they'll work.

Oh, and good on you.  
Not only for losing weight with her but caring enough to ask for advice. You could even join SparkPeople with her. There's even a place for the guys to hang out there. It's a very positive and supporting community that won't let you set goals that are harmful and has immensely improved my success as compared with previous weight loss attempts.

Thanks for the replies, ladies.  I don't know if this happens on SP, but she's on a site for the diet she's using and while it has great information about the diet and realistic goals, the support forums are full of people giving "attaboys" to people who, frankly, don't deserve huge kudos.  I understand the logic behind the forum not allowing brutally honest comments (especially when people post pictures) but it severely devalues any positive reniforcement received from the site.

She'll never be a petite girl, but she looks great and is pretty proportionate, if somewhat top heavy. She's also really hard to take a good picture of; round faces are the toughest for me to shoot.

The most productive part of SP, for me, has been the food and fitness trackers. It's a site that's just jammed packed with tools. She can read whatever groups she wants before joining one and doesn't even have to participate in the forum piece if she doesn't want to.
Some folks aren't photogenic, that's all. I'm certainly not. Perhaps celebrate the gains she's made by having your picture taken as a couple by a professional?

i'll be honest with you. I've always loved myself - inside and out. In the last month I've lost 17 lbs, and have become even more narcissistic as a result.

I would say take her lingerie shopping. Nothing makes a girl feel better than buying lacy items and showing them off. Maybe do a sexy photoshoot. Doesn't have to be in the nude - but take some glamorous photos of her, with her hair done and wearing a sultry outfit. She'll love it. She'll feel like a model by the end of it.

we've done a lot of shopping in the last couple weeks; a long formal gown for our engagenment party and a wedding dress

But last night she basically said "I think I'm doing well and then I see pictures."  I have a lot of trouble getting good shots of her face; I've done some tricks and shot her different ways, but I can either get images that show off how her body looks, or half-decent shots of her from the face up.  And i'm a pretty good photographer.  I hesitate to go to a full-time pro because if he can't make her look good, she wouldn't deal with it all that well.