diff --git a/libheif/api/libheif/heif_regions.cc b/libheif/api/libheif/heif_regions.cc
index 2d26f2fb0d..a7f98dac7d 100644
--- a/libheif/api/libheif/heif_regions.cc
+++ b/libheif/api/libheif/heif_regions.cc
@@ -333,8 +333,8 @@ struct heif_error heif_region_item_add_region_inline_mask(struct heif_region_ite
   region->mask_data.resize((width * height + 7) / 8);
   memset(region->mask_data.data(), 0, region->mask_data.size());
 
-  uint32_t mask_height = (uint32_t)heif_image_get_height(mask_image, heif_channel_Y);
-  uint32_t mask_width = (uint32_t)heif_image_get_width(mask_image, heif_channel_Y);
+  uint32_t mask_height = mask_image->image->get_height();
+  uint32_t mask_width = mask_image->image->get_width();
   int stride;
   uint8_t* p = heif_image_get_plane(mask_image, heif_channel_Y, &stride);
   uint64_t pixel_index = 0;
diff --git a/libheif/codecs/uncompressed/decoder_abstract.cc b/libheif/codecs/uncompressed/decoder_abstract.cc
index 7b66edbcd4..d858f4028a 100644
--- a/libheif/codecs/uncompressed/decoder_abstract.cc
+++ b/libheif/codecs/uncompressed/decoder_abstract.cc
@@ -58,7 +58,7 @@ void AbstractDecoder::buildChannelList(std::shared_ptr<HeifPixelImage>& img)
 
 void AbstractDecoder::processComponentSample(UncompressedBitReader& srcBits, const ChannelListEntry& entry, uint64_t dst_row_offset, uint32_t tile_column, uint32_t tile_x)
 {
-  uint64_t dst_col_number = tile_column * entry.tile_width + tile_x;
+  uint64_t dst_col_number = static_cast<uint64_t>(tile_column) * entry.tile_width + tile_x;
   uint64_t dst_column_offset = dst_col_number * entry.bytes_per_component_sample;
   int val = srcBits.get_bits(entry.bits_per_component_sample);
   memcpy(entry.dst_plane + dst_row_offset + dst_column_offset, &val, entry.bytes_per_component_sample);
diff --git a/libheif/image-items/grid.cc b/libheif/image-items/grid.cc
index d4e50a61e7..579136050d 100644
--- a/libheif/image-items/grid.cc
+++ b/libheif/image-items/grid.cc
@@ -266,7 +266,7 @@ Result<std::shared_ptr<HeifPixelImage>> ImageItem_Grid::decode_full_grid_image(c
 
   std::deque<tile_data> tiles;
   if (get_context()->get_max_decoding_threads() > 0)
-    tiles.resize(grid.get_rows() * grid.get_columns());
+    tiles.resize(static_cast<size_t>(grid.get_rows()) * static_cast<size-t>(grid.get_columns()));
 
   std::deque<std::future<Error> > errs;
 #endif
@@ -635,7 +635,7 @@ Result<std::shared_ptr<ImageItem_Grid>> ImageItem_Grid::add_new_grid_item(HeifCo
 
   // generate dummy grid item IDs (0)
   std::vector<heif_item_id> tile_ids;
-  tile_ids.resize(tile_rows * tile_columns);
+  tile_ids.resize(static_cast<size_t>(tile_rows) * static_cast<size_t>(tile_columns));
 
   // Connect tiles to grid
   file->add_iref_reference(grid_id, fourcc("dimg"), tile_ids);