I replied to your question in the Introductions forum, but figured I'd respond here as well. Transferring photos directly from your S3 to your Kindle might be difficult--I'm not aware of any linking cable that would allow for a connection between 2 devices like that. The easiest thing to do would be to upload your photos on your S3 to a cloud service (take your pick: Google+, Dropbox, Box, Skydrive, etc.), after which you should be able to access them from your Kindle, as long as you can install the same cloud app on the Kindle. Google+ would be the easiest one to use in an Android ecosystem (Google+'s gallery used to be Picasa), but I don't think you can easily install Google+ on a Kindle, due to Amazon's somewhat closed version Android. There are ways to hack a Kindle to make it into a full-fledged Android tablet (and therefore allow you to install Google+), but my guess is that you're not interested in tinkering. Dropbox and Box are available on the Amazon Appstore, so those are good alternatives.
For what it's worth, I don't think it would be easy to transfer photos directly from an iPhone to a Kindle, either.