Solid rectangular placeholder for non-supported images

Hello,

I read a news flux where each news item comes with a small image. Dillo
does not like the markup and replaces the image with a rectangular
placeholder with a solid colour fill. This happens even when images
loading is disabled (while other regular images are simply not
displayed, but not replaced by a filled rectangle), and the colour fill
seems to be randomly chosen at Dillo startup. I think this behaviour was
not intentional.

Right now the workaround is to not compile gif support. The placeholder
is then replaced by the alt text, which I prefer to some brightly
coloured rectangle.

Version: Dillo 3.0.5

Page: http://www.lemonde.fr/actualite-en-continu/

Snippet:

<img width="147" height="97"
data-item-type="article"
data-src="http://s2.lemde.fr/image/2016/02/26/147x97/4872606_7_843b_les-ministres-des-finances-et-gouverneurs-des_7ab22495ac426ebf4a37d8b5c3e51c2e.jpg"
src="data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw=="
data-lazyload="true"
alt="Les ministres..."
title="..."
onload="lmd.pic(this);"
onerror="lmd.pic(this);"
class="lazy-retina">

Thanks,
Jérôme