how to change the resoulotion of an external display

[cai876]

I have a g3 slot loading Imac, which I am reusing as a computer for a family member who is visually impaired. I have bought a 22" monitor that can display a resolution of 1680x1050. but I can not display more than 1024x768. Another problem is that I can't get it just to display on the external monitor, it uses both monitors with identical pictures.

 

[chrfr]

From what I remember, 1024x768 is the maximum resolution supported by that iMac.