Hope I don't get boo'd but I can see a little of the MIL. My kids are now 32-20. I wouldn't use the word "family" but may say, I want a picture with my kids and grandkids. (I actually wouldn't exclude my DIL but thinking what the MIL might be thinking). Even though I'm fine with my DIL, I still remember my kids being born, them getting in bed with me when they were sick, taking them to school etc...the grandkids, well they are an extension of my son. (not meaning they aren't of my DIL, just they bring back the memories of my son being little if that makes sense). So even though my DIL is family, those memories aren't there. So if I wanted a generation type photo, I'd want one with those that I gave birth to (or adopted) and the grandkids that are a part of my son. Not that it's leaving DIL out, it's more of a "look how far we've come" type of photo. Kind of a bloodline type photo. All photos are taken with everyone in it including DIL (and my sister's husbands/brother's wife) so never personally have had this done but I could see myself one day maybe asking for one. Not meaning to exclude but a bloodline type photo.
I would not do a tit for tat (send her one with you in it type of thing) as that does nothing but cause more hard feelings. I also don't understand the "it's his mom,he can do it" remarks unless that's normal in the household already. My exhusband worked 12 hours a day, I worked 6 so I always did all the shopping for holidays, birthdays for everyone (husband hated shopping anyway). Since I figured his family was now my family, I bought the presents as I would with my family. Can't say "I'm part of the family, I should be in the picture" but yet say, "it's his mother, he should buy all the presents".