scroll down until image is seen on screen

There is a specific image that I need to find
but the distance to scroll to it changes every two weeks.
But the horizontal spacing is the same, at 7 wheel downs.
So what I want to do is have findAll look for the image
and if it does not find anything then scroll down
7 more. Keep doing this scroll down 7 until it
finds the image.
So what am I doing wrong here ?

while(1):
    try:
        icons = findAll("1523914836809.png")
        if exists(icons):
            break
        else:
            wheel(Location(661, 465),WHEEL_DOWN,7)
    except Exception:
        pass

[error] script [ 796_795_garmin_charts_ctrl_eu_ifr_tdd_nd ] stopped with error at line --unknown--
[error] Error caused by: Traceback (most recent call last): File "C:\Users\marc.summers\Desktop.sikuli\796_795_garmin_charts_ctrl_eu_ifr_tdd_nd.sikuli\796_795_garmin_charts_ctrl_eu_ifr_tdd_nd.py", line 12, in <module> icons = findAll("1523914836809.png") File "C:\Users\marc.summers\Desktop.sikuli\796_795_garmin_charts_ctrl_eu_ifr_tdd_nd.sikuli\796_795_garmin_charts_ctrl_eu_ifr_tdd_nd.py", line 12, in <module> icons = findAll("1523914836809.png") Line 2469, in file Region.java
at org.sikuli.script.Region.findAll(Region.java:2469)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
org.sikuli.script.FindFailed: FindFailed: 1523914836809.png: (209x19) in S(0)[0,0 1920x1200] E:Y, T:3.0 Line 2469, in

file Region.java