[Pkg-gmagick-im-team] Bug#674718: imagemagick bug

[Andrew Deason]

On Tue, 29 May 2012 11:05:51 +0200
Bastien ROUCARIES <roucaries.bastien at gmail.com> wrote:

> Could you please describe what you are trying to achieve. Flatten
> means some special stuff in the gif context.
>
> And do not use geometry but resize or thumbnail operator.

I did not generate that command line invocation, so I can't really
explain the justification for it. It comes from the thumbnailing code in
Gallery, some imageboard software, and probably some other places. It
does not seem uncommon, and works as expected (at least, how I expected
it to work) in GraphicsMagick.

I'm not sure I understand upstream's response, though... is he trying to
say that it is expected that the provided example generates a jpg that
is tens of thousands pixels wide and tall? Even though the -size and
-geometry options specified a size of 217x159? Using -resize instead of
-geometry doesn't seem to change this behavior, but '-layers merge'
does.

> Are you trying to merge all the layer ? something like this :
> 
> convert -resize '217x159!' -layers merge  'foo.gif[0]' foo.jpg

The -layers option makes this incompatible with older ImageMagick
releases, and GraphicsMagick, which is possibly why various software
uses the other invocation.

> BTW according to upstream they are no security breach.

Reading the referenced link makes me think upstream did not understand
what I'm complaining about. While it is certainly reasonable for
imagemagick to generate images this large, and the failure mode is
understandable, why is imagemagick trying to create such a large image
in this case at all?

-- 
Andrew Deason
adeason at dson.org