Not necessary. Canon advertises some of their 3 colours 1 black printers like iP3000, i850, i560, i550, i475D as photo printers.
Correct me if I'm wrong, with improvements in inkjet technology, the difference in quality between so-called normal and photo printers has decreased and the term photo printer is more of a marketing term.
There is no fixed defination to a photo printer but my guess is that a photo printer should be able to accept different variety of media, have sufficient print quality to give photo-like results, may accept direct printing from camera or memory card and may have individual ink tanks or more more than 4 inks (CMYK).