I think it's because it's square rather than rectangular so to get it under the required number of pixels (150x150) it's hard to read the writing. This is it at that size anyway so if you want to use it just copy the link.
Thanks
I have it at 160 x 160 on Photobucket but it still just comes out huge on COL
I managed all the complicated bits (cutting out Jeff and Annie, making them bigger, moving them around, cloning the snow etc) albeit not very well, but resizing,which should be simple, has totally thrown me