Fix blank page issue caused by too strict correction on bpc

core/src/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp

Index: core/src/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp
diff --git a/core/src/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp b/core/src/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp
index 0362ff2e90cc48eea7fbc99f4eb80dc1b32f83e2..9497943fbd41d8ca0edfe63160b14f37e7c674d9 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 @@ void CPDF_DIBSource::ValidateDictParam() {
         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) {