diff --git a/newIDE/electron-app/scripts/app-build.js b/newIDE/electron-app/scripts/app-build.js
index 028f57dc20..763d76a4e0 100755
--- a/newIDE/electron-app/scripts/app-build.js
+++ b/newIDE/electron-app/scripts/app-build.js
@@ -21,17 +21,34 @@ const checkLibGDjsSize = () => {
         shell.exit(1);
       }
 
-      const sizeInMiB = stats.size / 1024 / 1024;
-      if (sizeInMiB > 2) {
+      // A release build is minified into a handful of very long lines, while a
+      // 'dev' or 'debug' build is not minified at all (tens of thousands of lines).
+      // Their sizes are too close to tell them apart, so check the line count.
+      const lineCount = fs
+        .readFileSync(path.join(appPublicPath, 'libGD.js'), 'utf8')
+        .split('\n').length;
+      if (lineCount > 1000) {
         shell.echo(
-          `❌ libGD.js size is too big (${sizeInMiB.toFixed(
-            2
-          )}MiB) - are you sure you're not trying to deploy the development version?`
+          `❌ libGD.js does not look minified (${lineCount} lines) - are you sure you're not trying to deploy the development version?`
         );
         shell.exit(1);
       }
 
-      shell.echo(`✅ libGD.js size seems correct (${sizeInMiB.toFixed(2)}MiB)`);
+      const sizeInMiB = stats.size / 1024 / 1024;
+      if (sizeInMiB > 4) {
+        shell.echo(
+          `❌ libGD.js size is too big (${sizeInMiB.toFixed(
+            2
+          )}MiB) - are you sure it was built properly?`
+        );
+        shell.exit(1);
+      }
+
+      shell.echo(
+        `✅ libGD.js seems correct (${sizeInMiB.toFixed(
+          2
+        )}MiB, ${lineCount} lines)`
+      );
 
       if (!fs.existsSync(path.join(appPublicPath, 'libGD.wasm'))) {
         shell.echo(
diff --git a/newIDE/web-app/scripts/deploy.js b/newIDE/web-app/scripts/deploy.js
index 3b00fb3a4c..0723418257 100644
--- a/newIDE/web-app/scripts/deploy.js
+++ b/newIDE/web-app/scripts/deploy.js
@@ -42,18 +42,33 @@ isGitClean()
           shell.exit(1);
         }
 
+        // A release build is minified into a handful of very long lines, while a
+        // 'dev' or 'debug' build is not minified at all (tens of thousands of lines).
+        // Their sizes are too close to tell them apart, so check the line count.
+        const lineCount = fs
+          .readFileSync(path.join(appPublicPath, 'libGD.js'), 'utf8')
+          .split('\n').length;
+        if (lineCount > 1000) {
+          shell.echo(
+            `❌ libGD.js does not look minified (${lineCount} lines) - are you sure you're not trying to deploy the development version?`
+          );
+          shell.exit(1);
+        }
+
         const sizeInMiB = stats.size / 1024 / 1024;
-        if (sizeInMiB > 2) {
+        if (sizeInMiB > 4) {
           shell.echo(
             `❌ libGD.js size is too big (${sizeInMiB.toFixed(
               2
-            )}MiB) - are you sure you're not trying to deploy the development version?`
+            )}MiB) - are you sure it was built properly?`
           );
           shell.exit(1);
         }
 
         shell.echo(
-          `✅ libGD.js size seems correct (${sizeInMiB.toFixed(2)}MiB)`
+          `✅ libGD.js seems correct (${sizeInMiB.toFixed(
+            2
+          )}MiB, ${lineCount} lines)`
         );
 
         if (!fs.existsSync(path.join(appPublicPath, 'libGD.wasm'))) {