Hey, I just sent some photos to a friend through mail but he wasn't able to open them. I sent them first using Mail and then using Thunderbird. I heard that there's some options to make "files compatible with all computers" or something along those lines but I can't find it anywhere. Can someone please show me where I can find this in Mail and in Thunderbird? Thanks. I know there was a post just like this a few days ago but I searched for 1/2 an hour and couldn't find it.