Image Remove Perimeter White Space

[hh]

> Ralph wrote:
> I will just have to go pixel by pixel and check
> left, top, right and bottom sides for any non-zero
> RGB and delete rows/columns until one of the sides
> has an RGB that is not zero.

Here is a comparison value for that.
Using javascript from a hidden browser widget autocropping
to opaque pixels needs (incl. transport) for a 500x500 sized
image around 100 ms.