Index: uspace/app/viewer/viewer.c
===================================================================
--- uspace/app/viewer/viewer.c	(revision c3d4b39b243e104029fd4c4b7a079d896faf3369)
+++ uspace/app/viewer/viewer.c	(revision 45208e22ecaca3517deacac9afba5d2e05986925)
@@ -40,4 +40,5 @@
 #include <stdlib.h>
 #include <str.h>
+#include <ui/filedialog.h>
 #include <ui/image.h>
 #include <ui/ui.h>
@@ -60,4 +61,5 @@
 	ui_image_t *image;
 	gfx_context_t *window_gc;
+	ui_file_dialog_t *dialog;
 
 	gfx_rect_t img_rect;
@@ -67,4 +69,5 @@
     gfx_rect_t *);
 static bool viewer_img_setup(viewer_t *, gfx_bitmap_t *, gfx_rect_t *);
+static errno_t viewer_window_create(viewer_t *);
 static void viewer_window_destroy(viewer_t *);
 
@@ -75,4 +78,14 @@
 	.close = wnd_close,
 	.kbd = wnd_kbd_event
+};
+
+static void file_dialog_bok(ui_file_dialog_t *, void *, const char *);
+static void file_dialog_bcancel(ui_file_dialog_t *, void *);
+static void file_dialog_close(ui_file_dialog_t *, void *);
+
+static ui_file_dialog_cb_t file_dialog_cb = {
+	.bok = file_dialog_bok,
+	.bcancel = file_dialog_bcancel,
+	.close = file_dialog_close
 };
 
@@ -132,4 +145,65 @@
 		}
 	}
+}
+
+/** File dialog OK button press.
+ *
+ * @param dialog File dialog
+ * @param arg Argument (viewer_t *)
+ * @param fname File name
+ */
+static void file_dialog_bok(ui_file_dialog_t *dialog, void *arg,
+    const char *fname)
+{
+	viewer_t *viewer = (viewer_t *) arg;
+	errno_t rc;
+
+	viewer->imgs_count = 1;
+	viewer->imgs = calloc(viewer->imgs_count, sizeof(char *));
+	if (viewer->imgs == NULL) {
+		printf("Out of memory.\n");
+		ui_quit(viewer->ui);
+		return;
+	}
+
+	viewer->imgs[0] = str_dup(fname);
+	if (viewer->imgs[0] == NULL) {
+		printf("Out of memory.\n");
+		ui_quit(viewer->ui);
+		return;
+	}
+
+	rc = viewer_window_create(viewer);
+	if (rc != EOK)
+		ui_quit(viewer->ui);
+
+	ui_file_dialog_destroy(dialog);
+	viewer->dialog = NULL;
+}
+
+/** File dialog cancel button press.
+ *
+ * @param dialog File dialog
+ * @param arg Argument (viewer_t *)
+ */
+static void file_dialog_bcancel(ui_file_dialog_t *dialog, void *arg)
+{
+	viewer_t *viewer = (viewer_t *) arg;
+
+	ui_file_dialog_destroy(dialog);
+	ui_quit(viewer->ui);
+}
+
+/** File dialog close request.
+ *
+ * @param dialog File dialog
+ * @param arg Argument (viewer_t *)
+ */
+static void file_dialog_close(ui_file_dialog_t *dialog, void *arg)
+{
+	viewer_t *viewer = (viewer_t *) arg;
+
+	ui_file_dialog_destroy(dialog);
+	ui_quit(viewer->ui);
 }
 
@@ -295,4 +369,5 @@
 error:
 	viewer_window_destroy(viewer);
+	ui_quit(viewer->ui);
 	return rc;
 }
@@ -313,4 +388,5 @@
 	int i;
 	unsigned u;
+	ui_file_dialog_params_t fdparams;
 
 	viewer = calloc(1, sizeof(viewer_t));
@@ -341,22 +417,19 @@
 	}
 
-	if (i >= argc) {
-		printf("No image files specified.\n");
-		print_syntax();
-		goto error;
-	}
-
-	viewer->imgs_count = argc - i;
-	viewer->imgs = calloc(viewer->imgs_count, sizeof(char *));
-	if (viewer->imgs == NULL) {
-		printf("Out of memory.\n");
-		goto error;
-	}
-
-	for (int j = 0; j < argc - i; j++) {
-		viewer->imgs[j] = str_dup(argv[i + j]);
-		if (viewer->imgs[j] == NULL) {
+	/* Images specified? */
+	if (i < argc) {
+		viewer->imgs_count = argc - i;
+		viewer->imgs = calloc(viewer->imgs_count, sizeof(char *));
+		if (viewer->imgs == NULL) {
 			printf("Out of memory.\n");
 			goto error;
+		}
+
+		for (int j = 0; j < argc - i; j++) {
+			viewer->imgs[j] = str_dup(argv[i + j]);
+			if (viewer->imgs[j] == NULL) {
+				printf("Out of memory.\n");
+				goto error;
+			}
 		}
 	}
@@ -373,7 +446,24 @@
 	viewer->ui = ui;
 
-	rc = viewer_window_create(viewer);
-	if (rc != EOK)
-		goto error;
+	if (viewer->imgs != NULL) {
+		/* We have images, create viewer window. */
+		rc = viewer_window_create(viewer);
+		if (rc != EOK)
+			goto error;
+	} else {
+		/* No images specified, browse for one. */
+		ui_file_dialog_params_init(&fdparams);
+		fdparams.caption = "Open Image";
+
+		rc = ui_file_dialog_create(viewer->ui, &fdparams,
+		    &viewer->dialog);
+		if (rc != EOK) {
+			printf("Error creating file dialog.\n");
+			goto error;
+		}
+
+		ui_file_dialog_set_cb(viewer->dialog, &file_dialog_cb,
+		    (void *)viewer);
+	}
 
 	ui_run(ui);
@@ -385,4 +475,6 @@
 	return 0;
 error:
+	if (viewer != NULL && viewer->dialog != NULL)
+		ui_file_dialog_destroy(viewer->dialog);
 	if (viewer != NULL && viewer->imgs != NULL) {
 		for (u = 0; u < viewer->imgs_count; u++) {