UI: account avatar

Fix image corners radius and limit size.

Change-Id: Ie7e0aaaf8244511a461e93c748af25c734c340fa
diff --git a/src/Constants.h b/src/Constants.h
index c5987c1..416f314 100644
--- a/src/Constants.h
+++ b/src/Constants.h
@@ -38,3 +38,5 @@
     /* download folder for incoming images*/
     NSString * const DownloadFolder = @"download_folder";
 }
+
+const CGFloat MAX_IMAGE_SIZE = 1024;