Flash Gadget error when uploading flash file

When uploading a flash file I get this error on the server side :

00:25:47,769 INFO [GadgetDocument] No width for resize picture, use default size
00:25:49,890 ERROR [ImagingComponent] Failed to get the ImageInfo for fileButtonRedBig.swf
java.lang.NumberFormatException: For input string: "no"
at java.lang.NumberFormatException.forInputString(NumberFormatException.java:48)
at java.lang.Integer.parseInt(Integer.java:447)
at java.lang.Integer.parseInt(Integer.java:497)
at org.nuxeo.ecm.platform.picture.api.ImageInfo.<init>(ImageInfo.java:43)
at org.nuxeo.ecm.platform.picture.api.ImageInfo.<init>(ImageInfo.java:51)
at org.nuxeo.ecm.platform.picture.magick.utils.ImageIdentifier.getInfo(ImageIdentifier.java:43)
at org.nuxeo.ecm.platform.picture.ImagingComponent.getImageInfo(ImagingComponent.java:232)
at org.nuxeo.opensocial.gadgets.GadgetDocument.getResizedBlobl(GadgetDocument.java:134)
at org.nuxeo.opensocial.gadgets.GadgetDocument.doPost(GadgetDocument.java:100)

We could improve the ImagingComponent, but what I don't get, is why the conversion is required on any file, even if this is not an image ...