saving pics

[bobsm8]

ok im using winxp pro been using it for ages now yrs probably..these past few mnths everytime i save a pic off the net i only get the option to save it as a bitmap image which means to save it as a j.peg i have to use the windows pic/fax viewer and resave it as a a j.peg..how do i change it back to save my images as j.pegs cause i cant find anyway of doing it..ive right clicked the image to "save as" but only the bitmap option is available ive suffered long enough with it now and its annoyed me to the max any ideas chaps?