diff --git a/Tests/LibGfx/TestImageDecoder.cpp b/Tests/LibGfx/TestImageDecoder.cpp
index d06992edf1..f0ccfe6170 100644
--- a/Tests/LibGfx/TestImageDecoder.cpp
+++ b/Tests/LibGfx/TestImageDecoder.cpp
@@ -417,6 +417,15 @@ TEST_CASE(test_jpeg_grayscale_with_app14)
     TRY_OR_FAIL(expect_single_frame_of_size(*plugin_decoder, { 80, 80 }));
 }
 
+TEST_CASE(test_jpeg_grayscale_with_weird_mcu_and_reset_marker)
+{
+    auto file = TRY_OR_FAIL(Core::MappedFile::map(TEST_INPUT("jpg/grayscale_mcu.jpg"sv)));
+    EXPECT(Gfx::JPEGImageDecoderPlugin::sniff(file->bytes()));
+    auto plugin_decoder = TRY_OR_FAIL(Gfx::JPEGImageDecoderPlugin::create(file->bytes()));
+
+    TRY_OR_FAIL(expect_single_frame_of_size(*plugin_decoder, { 320, 240 }));
+}
+
 TEST_CASE(test_jpeg_malformed_header)
 {
     Array test_inputs = {
diff --git a/Tests/LibGfx/test-inputs/jpg/grayscale_mcu.jpg b/Tests/LibGfx/test-inputs/jpg/grayscale_mcu.jpg
new file mode 100644
index 0000000000..c75b0f4f39
Binary files /dev/null and b/Tests/LibGfx/test-inputs/jpg/grayscale_mcu.jpg differ
diff --git a/Userland/Libraries/LibGfx/ImageFormats/JPEGLoader.cpp b/Userland/Libraries/LibGfx/ImageFormats/JPEGLoader.cpp
index d3477f879f..a9b2aef925 100644
--- a/Userland/Libraries/LibGfx/ImageFormats/JPEGLoader.cpp
+++ b/Userland/Libraries/LibGfx/ImageFormats/JPEGLoader.cpp
@@ -1301,6 +1301,11 @@ static ErrorOr<void> read_start_of_frame(JPEGStream& stream, JPEGLoadingContext&
         component.sampling_factors.horizontal = subsample_factors >> 4;
         component.sampling_factors.vertical = subsample_factors & 0x0F;
 
+        if (component_count == 1) {
+            // 4.8.2 Minimum coded unit: "If the compressed image data is non-interleaved, the MCU is defined to be one data unit."
+            component.sampling_factors = { 1, 1 };
+        }
+
         dbgln_if(JPEG_DEBUG, "Component subsampling: {}, {}", component.sampling_factors.horizontal, component.sampling_factors.vertical);
 
         if (i == 0) {