Add safe fallback format to thumbnail filter
Add safe fallback format to thumbnail filter

matthiask/django-content-editor,feincms/feincms,michaelkuty/feincms,matthiask/feincms2-content,nickburlett/feincms,joshuajonah/feincms,nickburlett/feincms,matthiask/django-content-editor,joshuajonah/feincms,matthiask/feincms2-content,matthiask/feincms2-content,mjl/feincms,pjdelport/feincms,michaelkuty/feincms,pjdelport/feincms,matthiask/django-content-editor,mjl/feincms,michaelkuty/feincms,mjl/feincms,joshuajonah/feincms,matthiask/django-content-editor,nickburlett/feincms,michaelkuty/feincms,feincms/feincms,joshuajonah/feincms,nickburlett/feincms,pjdelport/feincms,feincms/feincms