diff --git a/modules/images.py b/modules/images.py
index 3253847fe..cfdfb3384 100644
--- a/modules/images.py
+++ b/modules/images.py
@@ -54,11 +54,14 @@ def image_grid(imgs, batch_size=1, rows=None):
     params = script_callbacks.ImageGridLoopParams(imgs, cols, rows)
     script_callbacks.image_grid_callback(params)
 
-    w, h = imgs[0].size
-    grid = Image.new('RGB', size=(params.cols * w, params.rows * h), color='black')
+    w, h = map(max, zip(*(img.size for img in imgs)))
+    grid_background_color = ImageColor.getcolor(opts.grid_background_color, 'RGB')
+    grid = Image.new('RGB', size=(params.cols * w, params.rows * h), color=grid_background_color)
 
     for i, img in enumerate(params.imgs):
-        grid.paste(img, box=(i % params.cols * w, i // params.cols * h))
+        img_w, img_h = img.size
+        w_offset, h_offset = 0 if img_w == w else (w - img_w) // 2, 0 if img_h == h else (h - img_h) // 2
+        grid.paste(img, box=(i % params.cols * w + w_offset, i // params.cols * h + h_offset))
 
     return grid
 
diff --git a/scripts/xyz_grid.py b/scripts/xyz_grid.py
index 52e343c4f..606d72d42 100644
--- a/scripts/xyz_grid.py
+++ b/scripts/xyz_grid.py
@@ -375,16 +375,18 @@ def draw_xyz_grid(p, xs, ys, zs, x_labels, y_labels, z_labels, cell, draw_legend
         end_index = start_index + len(xs) * len(ys)
         grid = images.image_grid(processed_result.images[start_index:end_index], rows=len(ys))
         if draw_legend:
-            grid = images.draw_grid_annotations(grid, processed_result.images[start_index].size[0], processed_result.images[start_index].size[1], hor_texts, ver_texts, margin_size)
+            grid_max_w, grid_max_h = map(max, zip(*(img.size for img in processed_result.images[start_index:end_index])))
+            grid = images.draw_grid_annotations(grid, grid_max_w, grid_max_h, hor_texts, ver_texts, margin_size)
         processed_result.images.insert(i, grid)
         processed_result.all_prompts.insert(i, processed_result.all_prompts[start_index])
         processed_result.all_seeds.insert(i, processed_result.all_seeds[start_index])
         processed_result.infotexts.insert(i, processed_result.infotexts[start_index])
 
-    sub_grid_size = processed_result.images[0].size
+    # sub_grid_size = processed_result.images[0].size
     z_grid = images.image_grid(processed_result.images[:z_count], rows=1)
+    z_sub_grid_max_w, z_sub_grid_max_h = map(max, zip(*(img.size for img in processed_result.images[:z_count])))
     if draw_legend:
-        z_grid = images.draw_grid_annotations(z_grid, sub_grid_size[0], sub_grid_size[1], title_texts, [[images.GridAnnotation()]])
+        z_grid = images.draw_grid_annotations(z_grid, z_sub_grid_max_w, z_sub_grid_max_h, title_texts, [[images.GridAnnotation()]])
     processed_result.images.insert(0, z_grid)
     # TODO: Deeper aspects of the program rely on grid info being misaligned between metadata arrays, which is not ideal.
     # processed_result.all_prompts.insert(0, processed_result.all_prompts[0])