hot mail plus sizing attachments

I have two questions . First , I use mail , my friend uses hotmail , we both have Mac . When she receives in coming messages they are highlighted in a choice of colors . She can not see the highlighting, it's to dim . How can I make it brighter (darker) for her ? I do not mean the screen . Just the message . Second . She wants to send smaller attachments using hotmail . When I set things up for her I set Medium . Now I can't find where I did this . Mail has spoiled me . I think she is running Tiger . I did not check . Can these two prob's be fixed ?