diff --git a/src/core/context.c b/src/core/context.c
index 3c470e2..d29accc 100644
--- a/src/core/context.c
+++ b/src/core/context.c
@@ -53,9 +53,8 @@
     gchar *png;
     unsigned char hash[SHA_DIGEST_LENGTH]; /* == 20 */
     char xHash[SHA_DIGEST_LENGTH*2+1]; // always use two characters for hex encoding one byte
-    char tmp[3];
     xmpp_stanza_t *iq, *pubsub, *publish, *item, *data, *dt, *metadata, *info;
-    int i,j;
+    int i;
 
     /* 1. Create IQ 'set' stanza */
     iq = xmpp_stanza_new(bctx->ctx);
@@ -92,13 +91,8 @@
     memset(xHash, 0, 2*SHA_DIGEST_LENGTH+1);
     if(g_file_get_contents(bctx->avatarFile->str, &png, &length, NULL)) {
         SHA1((const unsigned char*)png, length, hash);
-        j = 0;
         for(i=0; i<SHA_DIGEST_LENGTH; i++) {
-            // we use a const string for convenience, can index it
-            sprintf(tmp, "%x", hash[i]);
-            xHash[j] = tmp[0];
-            xHash[++j] = tmp[1];
-            ++j;
+            sprintf(&xHash[i*2], "%02x", hash[i]);
         }
         xmpp_stanza_set_id(item, xHash);
     }
@@ -142,8 +136,6 @@
         xmpp_stanza_set_name(info, "info");
 
         xmpp_stanza_set_id(info, xHash);
-        xmpp_stanza_set_attribute(info, "height", "64");
-        xmpp_stanza_set_attribute(info, "width", "64");
         xmpp_stanza_set_attribute(info, "type", "image/png");
         xmpp_stanza_set_attribute(info, "bytes", bytes);
         xmpp_stanza_add_child(metadata, info);