diff --git a/src/apps/common/image.cpp b/src/apps/common/image.cpp
index a2a0f58f..9a67238a 100644
--- a/src/apps/common/image.cpp
+++ b/src/apps/common/image.cpp
@@ -98,12 +98,12 @@ unsigned int Image::numPlanes() const
 
 Span<uint8_t> Image::data(unsigned int plane)
 {
-	assert(plane <= planes_.size());
+	assert(plane < planes_.size());
 	return planes_[plane];
 }
 
 Span<const uint8_t> Image::data(unsigned int plane) const
 {
-	assert(plane <= planes_.size());
+	assert(plane < planes_.size());
 	return planes_[plane];
 }