diff --git a/rtengine/imageio.cc b/rtengine/imageio.cc
index 5f5573265..44297b10f 100644
--- a/rtengine/imageio.cc
+++ b/rtengine/imageio.cc
@@ -25,17 +25,17 @@
 #include <utility>
 #include <vector>
 
+#ifdef LIBJXL
+#include "jxl/decode_cxx.h"
+#include "jxl/resizable_parallel_runner_cxx.h"
+#endif
+
 #include <fcntl.h>
 #include <glib/gstdio.h>
 #include <png.h>
 #include <tiff.h>
 #include <tiffio.h>
 
-#ifdef LIBJXL
-#include "jxl/decode_cxx.h"
-#include "jxl/resizable_parallel_runner_cxx.h"
-#endif
-
 #ifdef _WIN32
 #include <winsock2.h>
 #else
@@ -849,8 +849,12 @@ int ImageIO::loadJXL(const Glib::ustring &fname)
     format.endianness = JXL_NATIVE_ENDIAN;
     format.align = 0;
 
-    std::string const contents = Glib::file_get_contents(fname);
-    std::vector<std::uint8_t> const compressed(contents.begin(), contents.end());
+    std::vector<std::uint8_t> const compressed = getFileData(fname);
+
+    if (compressed.empty()) {
+        g_printerr("Error: loadJXL failed to get data from file\n");
+        return IMIO_READERROR;
+    }
 
     // multi-threaded parallel runner.
     auto runner = JxlResizableParallelRunnerMake(nullptr);
@@ -894,7 +898,7 @@ int ImageIO::loadJXL(const Glib::ustring &fname)
             std::size_t icc_size = 0;
 
             if (JXL_DEC_SUCCESS !=
-#if JPEGXL_NUMERIC_VERSION < JPEGXL_COMPUTE_NUMERIC_VERSION(0,8,0)
+#if JPEGXL_NUMERIC_VERSION < JPEGXL_COMPUTE_NUMERIC_VERSION(0, 8, 0)
                     JxlDecoderGetICCProfileSize(dec.get(), &format, _PROFILE_, &icc_size)
 #else
                     JxlDecoderGetICCProfileSize(dec.get(), _PROFILE_, &icc_size)
@@ -907,7 +911,7 @@ int ImageIO::loadJXL(const Glib::ustring &fname)
                 icc_profile.resize(icc_size);
 
                 if (JXL_DEC_SUCCESS !=
-#if JPEGXL_NUMERIC_VERSION < JPEGXL_COMPUTE_NUMERIC_VERSION(0,8,0)
+#if JPEGXL_NUMERIC_VERSION < JPEGXL_COMPUTE_NUMERIC_VERSION(0, 8, 0)
                         JxlDecoderGetColorAsICCProfile(
                             dec.get(), &format, _PROFILE_,
                             icc_profile.data(), icc_profile.size())
@@ -927,9 +931,9 @@ int ImageIO::loadJXL(const Glib::ustring &fname)
                 g_printerr("Warning: Empty ICC data.\n");
             }
         } else if (status == JXL_DEC_NEED_IMAGE_OUT_BUFFER) {
-            // Note: If this assert is ever triggered, it should be changed
-            // to an assignment.  We want the maximum bit depth the decoder
-            // can provide regardless of the original encoding intent.
+            // Note: If assert is triggered, change to assignment.
+            // We want maximum bit depth from the decoder,
+            // regardless of the original encoding intent.
             assert(format.data_type == JXL_TYPE_FLOAT);
 
             if (JXL_DEC_SUCCESS !=
@@ -953,7 +957,7 @@ int ImageIO::loadJXL(const Glib::ustring &fname)
             // Decoding complete.  Decoder will be released automatically.
             break;
         } else if (status == JXL_DEC_NEED_MORE_INPUT) {
-            g_printerr("Error: Already provided all input\n");
+            g_printerr("Error: Decoder needs more input data\n");
             return IMIO_READERROR;
         } else if (status == JXL_DEC_ERROR) {
             g_printerr("Error: Decoder error\n");
@@ -962,7 +966,7 @@ int ImageIO::loadJXL(const Glib::ustring &fname)
             g_printerr("Error: Unknown decoder status\n");
             return IMIO_READERROR;
         }
-    }  // end grand decode loop
+    } // end grand decode loop
 
     std::size_t width = info.xsize;
     std::size_t height = info.ysize;
@@ -972,10 +976,10 @@ int ImageIO::loadJXL(const Glib::ustring &fname)
     std::size_t line_length = width * 3 * 4;
 
     for (std::size_t row = 0; row < height; ++row) {
-        setScanline(row, ((const unsigned char*)buffer.data()) + (row * line_length), 32);
+        setScanline(row, buffer.data() + (row * line_length), 32);
 
         if (pl && !(row % 100)) {
-            pl->setProgress((double)(row) / height);
+            pl->setProgress((double)(row + 1) / height);
         }
     }
 
diff --git a/rtengine/utils.cc b/rtengine/utils.cc
index f631a410a..6a8321d1c 100644
--- a/rtengine/utils.cc
+++ b/rtengine/utils.cc
@@ -19,6 +19,8 @@
 #include <cmath>
 #include <cstring>
 #include <cstdio>
+#include <fstream>
+#include <glibmm/convert.h>
 #include "rt_math.h"
 
 #include "utils.h"
@@ -222,6 +224,23 @@ void vflip(unsigned char* img, int w, int h)
     }
 }
 
+std::vector<std::uint8_t> getFileData(const Glib::ustring &filename)
+{
+    try {
+        const std::string fn = Glib::filename_from_utf8(filename);
+        std::ifstream instream(fn, std::ios::in | std::ios::binary);
+
+        std::vector<std::uint8_t> contents(
+            (std::istreambuf_iterator<char>(instream)),
+            std::istreambuf_iterator<char>());
+
+        instream.close();
+        return contents;
+    } catch (...) {
+        return {};
+    }
+}
+
 Glib::ustring getFileExtension(const Glib::ustring& filename)
 {
     const Glib::ustring::size_type lastdot_pos = filename.find_last_of('.');
diff --git a/rtengine/utils.h b/rtengine/utils.h
index 7ff16c79b..5dec93f51 100644
--- a/rtengine/utils.h
+++ b/rtengine/utils.h
@@ -18,6 +18,8 @@
  */
 #pragma once
 
+#include <vector>
+
 #include <type_traits>
 #include <glibmm/ustring.h>
 
@@ -43,6 +45,8 @@ constexpr typename std::underlying_type<ENUM>::type toUnderlying(ENUM value)
     return static_cast<typename std::underlying_type<ENUM>::type>(value);
 }
 
+std::vector<std::uint8_t> getFileData(const Glib::ustring &filename);
+
 // Return lower case extension without the "." or "" if the given name contains no "."
 Glib::ustring getFileExtension(const Glib::ustring& filename);
 // Return true if file has .jpeg or .jpg extension (ignoring case)