diff --git a/tools/chatgui/src/avatars/avatarcrop.cpp b/tools/chatgui/src/avatars/avatarcrop.cpp
index 74cb8fb2..d9ef46cd 100644
--- a/tools/chatgui/src/avatars/avatarcrop.cpp
+++ b/tools/chatgui/src/avatars/avatarcrop.cpp
@@ -106,18 +106,22 @@ bool selectAvatarCrop(const QString& source, QRectF& crop, QWidget* parent) {
     pool.start(QRunnable::create([source, &completion, dialog, view, status, buttons] {
         QImageReader reader(source); reader.setAutoTransform(true); const QSize size = reader.size(); QImage image;
         QString error;
+        const qint64 sourceBytes = QFileInfo(source).size(); const QByteArray format = reader.format();
         QSize orientedSize=size;
         if (reader.transformation() & QImageIOHandler::TransformationRotate90) orientedSize.transpose();
-        if (QFileInfo(source).size() > 0 && QFileInfo(source).size() <= AvatarCache::OriginalMaxBytes && size.width() > 0 && size.height() > 0 &&
-            qint64(size.width())*size.height() <= 16*1024*1024 &&
-            (reader.format()=="jpeg" || reader.format()=="png" || reader.format()=="webp")) {
+        if (sourceBytes < 1 || sourceBytes > AvatarCache::OriginalMaxBytes) error = QStringLiteral("source must contain 1..33554432 bytes");
+        else if (size.width() < 1 || size.height() < 1) error = reader.errorString();
+        else if (qint64(size.width())*size.height() > 16*1024*1024) error = QStringLiteral("source exceeds 16 megapixels");
+        else if (format != "jpeg" && format != "png" && format != "webp") error = QStringLiteral("unsupported image format");
+        else {
             if (qMax(size.width(), size.height()) > 1600) {
                 const QSize preview = size.scaled(1600, 1600, Qt::KeepAspectRatio);
                 reader.setScaledSize({qMax(1, preview.width()), qMax(1, preview.height())});
             }
             image = reader.read(); if (image.isNull()) error = reader.errorString();
-        } else error = QStringLiteral("source is unreadable, exceeds 32 MiB/16 MP, or has an unsupported format");
-        if (image.isNull()) DEBUG_WARN(DEBUG_CATEGORY_MEDIA, "avatar: editor decode failed source=%s reason=%s", qPrintable(source), qPrintable(error));
+        }
+        if (image.isNull()) DEBUG_WARN(DEBUG_CATEGORY_MEDIA, "avatar: editor decode failed source=%s bytes=%lld original=%dx%d format=%s reason=%s",
+            qPrintable(source), (long long)sourceBytes, size.width(), size.height(), format.constData(), qPrintable(error));
         if (!QMetaObject::invokeMethod(&completion, [dialog, view, image, orientedSize, status, buttons] {
             if (!dialog) return;
             if (image.isNull()) {