How, exactly, are you trying to import photos?
Are you using iPhoto?
If so, what version?
If not, what are you using?
Is iPhoto set to open when a camera, card reader or phone is attached. Check System Preferences > CD's & DVD's and iPhoto Preferences > General
What sort of Mac?
What OS version?
What version of iPhoto, if applicable?
Why has my mac stopped importing photos. Have tried from cameras, phones and card reader. Always worked before