diff --git a/ckanext/scheming/templates/scheming/form_snippets/upload.html b/ckanext/scheming/templates/scheming/form_snippets/upload.html
index d4798eaf..f57932cf 100644
--- a/ckanext/scheming/templates/scheming/form_snippets/upload.html
+++ b/ckanext/scheming/templates/scheming/form_snippets/upload.html
@@ -1,7 +1,8 @@
 {% import 'macros/form.html' as form %}
 
 {%- set is_upload = (data.url_type == 'upload') -%}
-{{ form.image_upload(
+
+{% call form.image_upload(
     data,
     errors,
     field_url=field.field_name,
@@ -12,8 +13,10 @@
     is_upload=is_upload,
     upload_label=h.scheming_language_text(field.upload_label),
     url_label=h.scheming_language_text(field.label),
+    classes=field.classes if 'classes' in field else ['control-medium'],
+    attrs=dict({"class": "form-control"}, **(field.get('form_attrs', {}))),
     placeholder=field.form_placeholder
-    )
-}}
-{# image_upload macro doesn't support call #}
-{%- snippet 'scheming/form_snippets/help_text.html', field=field -%}
+    ) 
+%}
+  {%- snippet 'scheming/form_snippets/help_text.html', field=field -%}
+{% endcall %}
\ No newline at end of file