Image selector generates invalid thumbnail links

[djkunkel]

When using the image selector designer, it is supposed to show the 0 named thumbnail in the simple editor, instead it generates urls with "tmb-.jpg" without the "0" in the url. This works OK with the internal media http handler, but fails when using an external provider (Like Amazon S3 since this url does not exist).

Getting urls like this:
https://.amazonaws.com/images/default-source/s3-test-public/wrd-background.tmb-.jpg?sfvrsn=0.39908983701160583

Instead of:
https://.amazonaws.com/images/default-source/s3-test-public/wrd-background.tmb-0.jpg?sfvrsn=0.39908983701160583