for this you can use isequalbin method..i am showing below

' Code for comparing two images

Set CompareUtil = CreateObject("Mercury.FileCompare")

IsEqualFlag = CompareUtil.IsEqualBin(Img1, Img2, 0, 1)

in above code 0 means in file compare class showing no

error ; syntax FC_NO_ERROR = 0

1 means in file compare class showing difference of

size; FC_DIFF_SIZE = 1