This sounds really terrible of me, but I'm going to say it anyway to get some insight... My FMIL wants to wear a red dress that she wore to my FSIL's wedding. It's a lovely dress, but I think it's going to clash with my color scheme. I'm using apricot and camo, and although my main focus isn't the camo, that still means there's going to be green accents throughout our decor and the men's tuxedo vests. I'm afraid that it might look Christmas-y in some pictures, like when she's standing next to my fiance and such. Even bigger than that, my FBIL is getting married a month and a half before us, and I'm sure she'll want to wear it then, too. IMO, I think she should wear something different. I mean, she's going to have three sets of pictures from three of her childrens' weddings, but she'll be wearing the same thing in all of them. I know that if it were me (and I realize it isn't), I would want to change it up a bit. This is probably pretty shallow of me to even consider, but I'd be a liar if I said it didn't bother me at least a little bit.
How do I nicely suggest that she find another dress? Money is very tight for her, so would it be in my better interest to offer to buy her a reasonably priced dress for our wedding day?