pixelchecksum alternative?

[GodForsakenSoul]

i'm trying to use checksum as a thing that remembers things. for an example, there's a thing on a site that is not text but a picture, that says "click here".

and i click there.

but that thing annoys me, so i made a script somewhat similar to this.

dim const $checksum = 43143423
while 1
   if pixelchecksum (xxx,yyy,aaa,bbb) = $checksum then
      mousemove (xxx,yyy)
      mouseclick ("left")
   endif
wend

now here's the thing: i compiled this, so i no longer have the au3 file. i ran the script again and it does not work.

further checking showed that the checksum i made earlier on the same picture changed into something else.

i need something more constant then checksum. suggestions?