diff --git a/ui/easydiffusion/backends/webui/impl.py b/ui/easydiffusion/backends/webui/impl.py
index 0e644bd5..a651a66f 100644
--- a/ui/easydiffusion/backends/webui/impl.py
+++ b/ui/easydiffusion/backends/webui/impl.py
@@ -195,7 +195,7 @@ def generate_images(
         cmd["init_images"] = [init_image]
         cmd["denoising_strength"] = prompt_strength
     if init_image_mask:
-        cmd["mask"] = init_image_mask
+        cmd["mask"] = init_image_mask if isinstance(init_image_mask, str) else img_to_base64_str(init_image_mask)
         cmd["include_init_images"] = True
         cmd["inpainting_fill"] = 1
         cmd["initial_noise_multiplier"] = 1
diff --git a/ui/easydiffusion/tasks/render_images.py b/ui/easydiffusion/tasks/render_images.py
index 2a46e6e6..ecb0226f 100644
--- a/ui/easydiffusion/tasks/render_images.py
+++ b/ui/easydiffusion/tasks/render_images.py
@@ -240,6 +240,10 @@ def generate_images_internal(
     if req.init_image is not None and int(req.num_inference_steps * req.prompt_strength) == 0:
         req.prompt_strength = 1 / req.num_inference_steps if req.num_inference_steps > 0 else 1
 
+    if req.init_image_mask:
+        req.init_image_mask = get_image(req.init_image_mask)
+        req.init_image_mask = resize_img(req.init_image_mask.convert("RGB"), req.width, req.height, clamp_to_8=True)
+
     backend.set_options(
         context,
         output_format=output_format.output_format,