diff --git a/components/formats-gpl/src/loci/formats/in/ZeissCZIReader.java b/components/formats-gpl/src/loci/formats/in/ZeissCZIReader.java
index 95d7f36e879..c05d47da625 100644
--- a/components/formats-gpl/src/loci/formats/in/ZeissCZIReader.java
+++ b/components/formats-gpl/src/loci/formats/in/ZeissCZIReader.java
@@ -734,7 +734,6 @@ protected void initFile(String id) throws FormatException, IOException {
     convertPixelType(planes.get(0).directoryEntry.pixelType);
 
     // remove any invalid SubBlocks
-
     int bpp = FormatTools.getBytesPerPixel(getPixelType());
     if (isRGB()) {
       bpp *= (getSizeC() / originalC);
@@ -743,16 +742,18 @@ protected void initFile(String id) throws FormatException, IOException {
     for (int i=0; i<planes.size(); i++) {
       long planeSize = (long) planes.get(i).x * planes.get(i).y * bpp;
       int compression = planes.get(i).directoryEntry.compression;
-      if (compression == UNCOMPRESSED || compression == JPEGXR) {
+      boolean isCompressed = compression == JPEGXR || compression == ZSTD_0 || compression == ZSTD_1;
+      if (compression == UNCOMPRESSED || isCompressed) {
         long size = planes.get(i).dataSize;
         if (size < planeSize || planeSize >= Integer.MAX_VALUE || size < 0) {
           // check for reduced resolution in the pyramid
           DimensionEntry[] entries = planes.get(i).directoryEntry.dimensionEntries;
           int pyramidType = planes.get(i).directoryEntry.pyramidType;
-          if ((pyramidType == 1 || pyramidType == 2 || compression == JPEGXR) &&
-            (compression == JPEGXR || size == entries[0].storedSize * entries[1].storedSize * bpp))
+          if (isCompressed || 
+              ((pyramidType == 1 || pyramidType == 2 ) && (size == entries[0].storedSize * entries[1].storedSize * bpp)))
           {
-            int scale = planes.get(i).x / entries[0].storedSize;
+        	// circumvent integer arithmetic rounding issue by using floating point precision calculation (see issue #4102)
+        	int scale = (int)((double)planes.get(i).x / (double)entries[0].storedSize + 0.5);
             if (scale == 1 || (((scale % 2) == 0 || (scale % 3) == 0) && allowAutostitching())) {
               if (scale > 1 && scaleFactor == 0) {
                 scaleFactor = scale % 2 == 0 ? 2 : 3;
@@ -4186,7 +4187,7 @@ public byte[] readPixelData(RandomAccessInputStream s, Region tile, byte[] buf)
             }
           }
           else {
-            LOGGER.warn("ZSTD-1 compression used, but no high/low byte unpacking");
+            LOGGER.debug("ZSTD-1 compression used, but no high/low byte unpacking");
             data = decoded;
           }