iMessage from my macbookpro

Hey, Just wondering if anyone else has this problem. Idk, maybe something I'm not doing in settings but its very frustrating. I still have not updated to the most recent update for since the last time i updated i can no longer share things via iMessage. Normally when i wanted to share a photo from iPhoto, i just clicked share and the option iMessage and bam it immediately put it into iMessage, same thing with a website. now although i still have the option when i click on that option i get nothing. Very disappointing. also before this last update i could also use iMessage to text message people that didn't even have iMessage or an iPhone, such as my husband. that no longer is the case either.

does anyone know what I'm doing wrong> or not doing??

Thanks

Tton