set default filename to pdf and allow attr for image

opentech/apply/stream_forms/blocks.py

@@ -318,11 +318,17 @@ class UploadableMediaBlock(OptionalFormFieldBlock):
 
 class ImageFieldBlock(UploadableMediaBlock):
     field_class = forms.ImageField
+    widget = ClearableFileInput
 
     class Meta:
         label = _('Image field')
         icon = 'image'
 
+    def get_field_kwargs(self, struct_value):
+        kwargs = super().get_field_kwargs(struct_value)
+        kwargs['widget'] = self.get_widget(struct_value)(attrs={'accept': 'image/*'})
+        return kwargs
+
 
 class FileFieldBlock(UploadableMediaBlock):
     """This doesn't know how to save the uploaded files

opentech/apply/stream_forms/testing/factories.py

@@ -143,8 +143,10 @@ class UploadableMediaFactory(FormFieldBlockFactory):
     def make_answer(cls, params=dict()):
         params = params.copy()
         params.setdefault('data', b'this is some content')
+        if params.get('filename') is None:
+            params['filename'] = 'example.pdf'
         file_name, file = cls.default_value()._make_content(params)
-        return SimpleUploadedFile(file_name + '.pdf', file.read())
+        return SimpleUploadedFile(file_name, file.read())
 
 
 class ImageFieldBlockFactory(UploadableMediaFactory):