diff --git a/src/main/java/qupath/lib/images/servers/omero/OmeroWebImageServer.java b/src/main/java/qupath/lib/images/servers/omero/OmeroWebImageServer.java
index a04ff6e..cb854e1 100644
--- a/src/main/java/qupath/lib/images/servers/omero/OmeroWebImageServer.java
+++ b/src/main/java/qupath/lib/images/servers/omero/OmeroWebImageServer.java
@@ -281,8 +281,28 @@ else if (map.has("channels")) {
 			int levels = map.getAsJsonPrimitive("levels").getAsInt();
 			if (levels > 1) {
 				JsonObject zoom = map.getAsJsonObject("zoomLevelScaling");
+        double aspectRatio = (double) sizeX / sizeY;
+        logger.debug("image aspect ratio = {}", aspectRatio);
 				for (int i = 0; i < levels; i++) {
-					levelBuilder.addLevelByDownsample(1.0 / zoom.getAsJsonPrimitive(Integer.toString(i)).getAsDouble());
+          double rawZoomFactor = zoom.getAsJsonPrimitive(Integer.toString(i)).getAsDouble();
+          logger.debug("level = {}, rawZoomFactor = {}", i, rawZoomFactor);
+
+          // level width and height calculation are best-effort,
+          // given that we cannot currently get the precise dimensions
+          // this needs to be fixed once web API is fixed
+
+          // we expect the width calculation to be accurate, as zoomLevelScaling
+          // was calculated based upon the resolution widths alone
+          int levelWidth = (int) Math.floor(rawZoomFactor * sizeX);
+
+          // now apply the image aspect ratio to find the height
+          // this assumes that the aspect ratio remains consistent across the whole pyramid
+          // subtract 1 to account for potential rounding issues
+          int levelHeight = (int) Math.floor(levelWidth / aspectRatio) - 1;
+
+          logger.debug("  level width = {}, level height = {}", levelWidth, levelHeight);
+
+          levelBuilder.addLevel(1 / rawZoomFactor, levelWidth, levelHeight);
 				}
 			} else {
 				levelBuilder.addFullResolutionLevel();