"==" is an expression, or a test so will return either true, or false depending on if the test comes back as true (e.g. 1 == 1 returns true, 1 == 2 returns false)
"=" is setting the value of the field and will return true if it manages to set the value (I have several times put in only a single "=" by mistake and spent a long time wondering why it seemed to be doing somethign when it shouldn't)
As for not working, check what the radio groups are returning as their raw values by using:
xfa.host.messageBox("" +radioGroup1.rawValue );
It might be set to associate the radio's with a numerical value (In the Object > Binding tab).
when i clear data with a reset data button, my image remains visible. so i want to hide it whenever the reset data button is clicked. what i did was, i entered the script Im_Jye.presence = "hidden"; onto the click event of the reset data button after an existing script "xfa.host.resetdata();"