There was a problem with your picture. Probably too big.

Start by reading the error message. Try uploading a very tiny image, like the one generated by this script:

#!/usr/bin/perl -w
use MIME::Base64;
open OUT,'>','tiny.gif' or die "ooops: $!";
binmode OUT;
print OUT decode_base64('R0lGODlhAQABAPABAIor4v///yH5BAAAAAAALAAAAAABA
+AEAAAICRAEAOw==');
close OUT;
[download]

Read the API rules. Perhaps you have hit a usage limit.

Alexander