diff --git a/kimgio/ico.cpp b/kimgio/ico.cpp
index 2b9ca6d5..899d547e 100644
--- a/kimgio/ico.cpp
+++ b/kimgio/ico.cpp
@@ -300,17 +300,16 @@ QList<QByteArray> ICOPlugin::mimeTypes() const
 
 QImageIOPlugin::Capabilities ICOPlugin::capabilities(QIODevice *device, const QByteArray &format) const
 {
-    if (format == s_icopluginformat)
+    if (format == s_icopluginformat) {
         return QImageIOPlugin::Capabilities(QImageIOPlugin::CanRead);
-    if (!format.isEmpty())
+    }
+    if (!device || !device->isOpen()) {
         return 0;
-    if (!device->isOpen())
-        return 0;
-
-    QImageIOPlugin::Capabilities cap;
-    if (device->isReadable() && ICOHandler::canRead(device))
-        cap |= QImageIOPlugin::CanRead;
-    return cap;
+    }
+    if (device->isReadable() && ICOHandler::canRead(device)) {
+        return QImageIOPlugin::Capabilities(QImageIOPlugin::CanRead);
+    }
+    return 0;
 }
 
 QImageIOHandler *ICOPlugin::create(QIODevice *device, const QByteArray &format) const
diff --git a/kimgio/jp2.cpp b/kimgio/jp2.cpp
index 9ec3b732..20908318 100644
--- a/kimgio/jp2.cpp
+++ b/kimgio/jp2.cpp
@@ -305,15 +305,16 @@ QList<QByteArray> JP2Plugin::mimeTypes() const
 
 QImageIOPlugin::Capabilities JP2Plugin::capabilities(QIODevice *device, const QByteArray &format) const
 {
-    if (format == s_jp2pluginformat)
+    if (format == s_jp2pluginformat) {
         return QImageIOPlugin::Capabilities(QImageIOPlugin::CanRead);
-    if (!device->isOpen())
+    }
+    if (!device || !device->isOpen()) {
         return 0;
-
-    QImageIOPlugin::Capabilities cap;
-    if (device->isReadable() && JP2Handler::canRead(device))
-        cap |= QImageIOPlugin::CanRead;
-    return cap;
+    }
+    if (device->isReadable() && JP2Handler::canRead(device)) {
+        return QImageIOPlugin::Capabilities(QImageIOPlugin::CanRead);
+    }
+    return 0;
 }
 
 QImageIOHandler *JP2Plugin::create(QIODevice *device, const QByteArray &format) const
diff --git a/kimgio/jpeg.cpp b/kimgio/jpeg.cpp
index 937fa655..2a99753a 100644
--- a/kimgio/jpeg.cpp
+++ b/kimgio/jpeg.cpp
@@ -183,17 +183,16 @@ QList<QByteArray> JPEGPlugin::mimeTypes() const
 
 QImageIOPlugin::Capabilities JPEGPlugin::capabilities(QIODevice *device, const QByteArray &format) const
 {
-    if (format == s_jpegpluginformat)
+    if (format == s_jpegpluginformat) {
         return QImageIOPlugin::Capabilities(QImageIOPlugin::CanRead);
-    if (!format.isEmpty())
+    }
+    if (!device || !device->isOpen()) {
         return 0;
-    if (!device->isOpen())
-        return 0;
-
-    QImageIOPlugin::Capabilities cap;
-    if (device->isReadable() && JPEGHandler::canRead(device))
-        cap |= QImageIOPlugin::CanRead;
-    return cap;
+    }
+    if (device->isReadable() && JPEGHandler::canRead(device)) {
+        return QImageIOPlugin::Capabilities(QImageIOPlugin::CanRead);
+    }
+    return 0;
 }
 
 QImageIOHandler *JPEGPlugin::create(QIODevice *device, const QByteArray &format) const
diff --git a/kimgio/raw.cpp b/kimgio/raw.cpp
index 92464730..df68dafe 100644
--- a/kimgio/raw.cpp
+++ b/kimgio/raw.cpp
@@ -186,17 +186,16 @@ QList<QByteArray> RAWPlugin::mimeTypes() const
 
 QImageIOPlugin::Capabilities RAWPlugin::capabilities(QIODevice *device, const QByteArray &format) const
 {
-    if (format == s_rawpluginformat)
+    if (format == s_rawpluginformat) {
         return QImageIOPlugin::Capabilities(QImageIOPlugin::CanRead);
-    if (!format.isEmpty())
+    }
+    if (!device || !device->isOpen()) {
         return 0;
-    if (!device->isOpen())
-        return 0;
-
-    QImageIOPlugin::Capabilities cap;
-    if (device->isReadable() && RAWHandler::canRead(device))
-        cap |= QImageIOPlugin::CanRead;
-    return cap;
+    }
+    if (device->isReadable() && RAWHandler::canRead(device)) {
+        return QImageIOPlugin::Capabilities(QImageIOPlugin::CanRead);
+    }
+    return 0;
 }
 
 QImageIOHandler *RAWPlugin::create(QIODevice *device, const QByteArray &format) const
diff --git a/kimgio/webp.cpp b/kimgio/webp.cpp
index 59d4f017..c601fc85 100644
--- a/kimgio/webp.cpp
+++ b/kimgio/webp.cpp
@@ -203,21 +203,17 @@ QList<QByteArray> WebPPlugin::mimeTypes() const
 QImageIOPlugin::Capabilities WebPPlugin::capabilities(QIODevice *device, const QByteArray &format) const
 {
     if (format == "webp") {
-        return Capabilities(CanRead | CanWrite);
+        return QImageIOPlugin::Capabilities(QImageIOPlugin::CanRead | QImageIOPlugin::CanWrite);
     }
-    if (!format.isEmpty()) {
+    if (!device || !device->isOpen()) {
         return 0;
     }
-    if (!device->isOpen()) {
-        return 0;
-    }
-
-    Capabilities cap;
+    QImageIOPlugin::Capabilities cap;
     if (device->isReadable() && WebPHandler::canRead(device)) {
-        cap |= CanRead;
+        cap |= QImageIOPlugin::CanRead;
     }
     if (device->isWritable()) {
-        cap |= CanWrite;
+        cap |= QImageIOPlugin::CanWrite;
     }
     return cap;
 }