[SOLVED] Thumbnail confusion - sudden resize without provocation

Hi, I have some confusion over my gallery's thumbnails.

All has worked fine and we love the gallery software but recently, something happened and the thumbnails changed.

They used to be snug together with a pixel or two border, sized at 100Xwhatever pixels, sitting 5 across and 2 down in a box next to the selected picture. Everything was lovely. Strangely, without any interaction or provocation, they now are confusingly small, spaced out and not snug together.

I have no idea why this has happened but thought it best to simply ask the knowledgeable community rather than painstakingly work through code.
Someone here may be able to give me the simplest of answers causing me to :facepalm: but I thought it best to ask first rather than sweat.

TIA, Here are my details -

Last Run Details:

Gallery URL = http://www.christianthelionprints.com/prints/main.php
Gallery version = 2.3 core 1.3.0
API = Core 7.54, Module 3.9, Theme 2.6, Embed 1.5
PHP version = 5.2.6 apache2handler
Webserver = Apache
Database = mysqli 5.0.81-community-log, lock.system=flock
Toolkits = ArchiveUpload, Exif, Ffmpeg, Getid3, LinkItemToolkit, Thumbnail, Gd, ImageMagick, jpegtran, SquareThumb
Acceleration = none/900, none/0
Operating system = Linux funky.cirtexhosting.com 2.6.18-128.1.14.el5PAE #1 SMP Wed Jun 17 07:15:54 EDT 2009 i686
Default theme = carbon
gettext = enabled
Locale = en_GB
Browser = Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.0; WOW64; Trident/4.0; SLCC1; .NET CLR 2.0.50727; .NET CLR 3.0.30729; .NET CLR 3.5.30729)
Rows in GalleryAccessMap table = 38
Rows in GalleryAccessSubscriberMap table = 16
Rows in GalleryUser table = 3
Rows in GalleryItem table = 13
Rows in GalleryAlbumItem table = 1
Rows in GalleryCacheMap table = 0

http://www.christianthelionprints.com/prints/main.php - This is the main gallery section. Everything is fine here (as far as I can tell)
http://www.christianthelionprints.com/prints/v/CTL-001.jpg.html - This is a gallery item page , where you can see the confusingly small and strangely arranged thumbnails.

http://www.christianthelionprints.com/prints/phpinfo.php - Here is the PHP info file, loaded on to server.

I have GD, ImageMagick and JpegTran, set ImageMagick then GD in toolkit priority. My PHP memory limit is 128MB, I found this out through my host's WebUI.

I hope someone can give me some assistance as to where to find the offending code, options in the WebUI to sort out this problem or steps to take in order to rectify the problem. I didn't want to start uninstalling and reinstalling things before asking if there was a simple explaination.

Thank you in advance.

I do, and have removed it (deleted via FTP)

I also went in to the carbon theme template in WebUI and unchecked "use micro thumbs"

I now have no thumbnails whatsoever.

Advice from now?

I do that and they're back to the horrible way they were before...

Problem has been rectified. Thread can be closed if needed.