diff --git a/core/src/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp b/core/src/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp
index 0362ff2..9497943 100644
--- a/core/src/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp
+++ b/core/src/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp
@@ -957,8 +957,11 @@
         m_bpc = 1;
         m_nComponents = 1;
       }
-      if (filter == FX_BSTRC("RunLengthDecode") ||
-          filter == FX_BSTRC("DCTDecode")) {
+      if (filter == FX_BSTRC("RunLengthDecode")) {
+        if (m_bpc != 1) {
+          m_bpc = 8;
+        }
+      } else if (filter == FX_BSTRC("DCTDecode")) {
         m_bpc = 8;
       }
     } else if (pFilter->GetType() == PDFOBJ_ARRAY) {
diff --git a/testing/resources/pixel/bug_512557.in b/testing/resources/pixel/bug_512557.in
new file mode 100644
index 0000000..5f35334
--- /dev/null
+++ b/testing/resources/pixel/bug_512557.in
Binary files differ
diff --git a/testing/resources/pixel/bug_512557_expected.pdf.0.png b/testing/resources/pixel/bug_512557_expected.pdf.0.png
new file mode 100644
index 0000000..66c73ae
--- /dev/null
+++ b/testing/resources/pixel/bug_512557_expected.pdf.0.png
Binary files differ