The image frequency is twice the IF frequency away from the desired station. I suspect that FM receivers use low side LO so the image is lower than the desired signal.
As far as reception goes, the RF amplifier has selectivity from tuned circuits and broadcast stations are high power so there is a low probability that any signals on the image frequency will interfere with the broadcast reception.
for any radio receiver image frequency fi=fs+2if
where fi is image freq , fs: is signal freq and, if: is the intermediate frequency which will vary depend on fm(10.7mhz) or am(455khz) receiver.
double spotting will occur for the calculated image freq.
for any other details refer electronic communication by kennedy.
The IF frequency for FM is 10.7 MHz. Therefore, the image is 21.4 MHz away from the station. Therefore, for FM radio, which only has a range of 88 MHz - 108 MHz (20 MHz), the image is not within the FM receiver tuning range. So, you can't get an image unless you have a general receiver.
The front end filtering in FM receivers is never perfect.
The image frequency can fall on aircraft frequencys above 108MHz or on low-VHF frequencys somtimes used by taxi's and other mobile radio users.