Update defined_page.php for secure images

This is to fix a problem where images for the catalog-side are called for display from Admin SSL pages and were throwing errors because they were displayed insecurely.
<a href='#crh-start'></a><a href='#crh-data-%7B%22processed%22%3A%20%5B%22https%3A//github.com/zencart/zc-v1-series/pull/146%23issuecomment-54177015%22%2C%20%22https%3A//github.com/zencart/zc-v1-series/pull/146%23issuecomment-55299774%22%2C%20%22https%3A//github.com/zencart/zc-v1-series/pull/146%23issuecomment-55299788%22%5D%2C%20%22comments%22%3A%20%7B%22General%20Comment%22%3A%20%7B%22html_url%22%3A%20%22https%3A//github.com/zencart/zc-v1-series/pull/146%23issuecomment-54177015%22%2C%20%22comments%22%3A%20%5B%7B%22body%22%3A%20%22%3A%2B1%3A%20%5Cr%5CnSatisfied%20that%20the%20code%20is%20consistent%20with%20patterns%20embraced%20throughout.%22%2C%20%22created_at%22%3A%20%222014-09-02T16%3A15%3A53Z%22%2C%20%22user%22%3A%20%7B%22avatar_url%22%3A%20%22https%3A//avatars.githubusercontent.com/u/404472%3Fv%3D2%22%2C%20%22html_url%22%3A%20%22https%3A//github.com/drbyte%22%7D%7D%2C%20%7B%22body%22%3A%20%22%3A%2B1%3A%20%22%2C%20%22created_at%22%3A%20%222014-09-11T17%3A37%3A07Z%22%2C%20%22user%22%3A%20%7B%22avatar_url%22%3A%20%22https%3A//avatars.githubusercontent.com/u/227354%3Fv%3D2%22%2C%20%22html_url%22%3A%20%22https%3A//github.com/zcwilt%22%7D%7D%2C%20%7B%22body%22%3A%20%22%3Ashipit%3A%22%2C%20%22created_at%22%3A%20%222014-09-11T17%3A37%3A14Z%22%2C%20%22user%22%3A%20%7B%22avatar_url%22%3A%20%22https%3A//avatars.githubusercontent.com/u/227354%3Fv%3D2%22%2C%20%22html_url%22%3A%20%22https%3A//github.com/zcwilt%22%7D%7D%5D%2C%20%22title%22%3A%20%22General%20Comment%22%7D%7D%2C%20%22approved%22%3A%20%7B%22https%3A//github.com/zcwilt%22%3A%20%7B%22avatar_url%22%3A%20%22https%3A//avatars.githubusercontent.com/u/227354%3Fv%3D2%22%7D%7D%7D'></a>
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- [x] <a href='#crh-comment-General Comment'></a> <img src='http://www.codereviewhub.com/site/github-completed.png' height=16 width=60>&nbsp;<b><a href='https://github.com/zencart/zc-v1-series/pull/146#issuecomment-54177015'>General Comment</a></b>
- <a href='https://github.com/drbyte'><img border=0 src='https://avatars.githubusercontent.com/u/404472?v=2' height=16 width=16'></a> :+1:
Satisfied that the code is consistent with patterns embraced throughout.


<a href='https://www.codereviewhub.com/zencart/zc-v1-series/pull/146?mark_as_completed=1'><img src='http://www.codereviewhub.com/site/github-mark-as-completed.png' height=26></a>&nbsp;<a href='https://www.codereviewhub.com/zencart/zc-v1-series/pull/146?approve=1'><img src='http://www.codereviewhub.com/site/github-approve.png' height=26></a>&nbsp;<a href='https://www.codereviewhub.com/zencart/zc-v1-series/pull/146?approve=0'><img src='http://www.codereviewhub.com/site/github-undo-approve.png' height=26></a>&nbsp;<a href='https://github.com/zencart/zc-v1-series/pull/146'><img src='http://www.codereviewhub.com/site/github-refresh.png' height=26></a>
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