calculation based on the size of the image file. Okay, to avoid all
you folks from going to see what bit of dreck I came up with, here it
is:

    my $sb     = stat($imagepath);
    my $chunks = $sb->size / (1024 * 1024);
    $maxwait   = int((($chunks / 100.0) * 25) + (4 * 60));

Note the replacement of one hardwired number (15) with several dozen
new ones!

I like it anyway, cause I hate waiting 2*15 minutes when a 60 second
load fails.