cubicweb-file #1913860 thumbnail/resized image are generated as png whatever the image type [resolved]

so we can ends up with a 'toto.jpg' file actully contains png data when automatic resizing is activated

prioritynormal
typebug
done in1.10.4
load0.200
load left0.000
closed by#f7a93d8aa445 closes #1913860: thumbnail/resized image are generated as png whatever the image type / extension