Hello Thiru,
if you mean picture resolution you need to define a resolution as described here:
Open JavaClient via WebStart -> Click Help -> Index -> A help tab opens -> Templates (basics) -> General Operations -> Media
After that you can refer to the just defined resolution using the following code snippet:
$CMS_REF(st_picture, resolution:"yourJustDefinedResolution")$
where st_picture ist the name of your <CMS_INPUT_PICTURE> form element.
Yours sincerely
Ismail