We can't force it to convert it to ChannelFirst
This behavior should be configurable. Can't force the user to use ChannelFirst patch (specially in case of png..)

LoadImaged => MyTransform => EnsureChannelFirst
LoadWSI => MyTransform => EnsureChannelFirst

Little not consistent with LoadImage and LoadWSI .. in the 2nd case, I can't use my transform same as first case.. so I have to do something like this as a workaround
LoadWSI => AsChannelLast => MyTransform => EnsureChannelFirst

better to be consistent with what LoadImage does..