Moved to new server, now product images not showing in Admin

Version 1.5.6.4

I just moved a site to a new server and after we got the new SSL in place, I went to the Admin section and the product images are not showing up (see attached image). The images appear to be on the server, but they're just not showing up here. When I hover over one of these missing images for its link, I see this sort of address:

https://www.mywebsite.com/admin/HTTPS_CATALOGimage/cache//data/passenger-4/AZL_hvyw_CO_71145-2s-40x40.jpg

When I should normally expect to see something much more clear, like this (from another site of mine):
https://www.mywebsite.com/image/cache/data/caboose/AZL_UP_CA1_40006b_slant-40x40.jpg

I checked the Error Log and I get lots of this message:
2017-03-10 19:36:50 - PHP Notice: Use of undefined constant HTTPS_CATALOG - assumed 'HTTPS_CATALOG' in /home/sandsugar/public_html/admin/model/tool/image.php on line 34

Overall It looks like the path to the images in the Admin and individual product sections are seriously messed up but I'm not clear on how this would have happened. On the front end of the store, the images are appearing normally. Any help getting me straightened out would be greatly appreciated.

Thanks, John

Check your config.php files both in root of site and folder admin.
Most likely config.php in admin folder has some errors in absolute path to images

Yes, that was it of course... and I thought I had corrected this. I actually had the root and admin config files mixed up. All good now (except for email which "was" working and now is not... that'll be a new thread

Thank you for your help.

John