The thumbnails in my item galleries are not showing, This is happening in both the Front and Back end. The lightbox image does show when the thumbnail is clicked though.

I have tried it with different templates and I have also tried unpublishing every extension in turn in case of conflicts but I cannot get the thumbnails to show, they are just blank.
Please see screenshots of the front and backend.
I have also tried uninstalling and reinstalling K2 and Simple Image Gallery Pro.

I am running the latest version of K2 on Joomla 1.7

Can anyone help with this?

Hi Moraelin,

You might want to check the permission of your cache folder. There was a similar issue reported here

Do you have spaces in the filenames of the gallery items? If so, remove them.

Thanks Kannan
I've been using an extension called Cachecleaner by NoNumber which quickly cleans your cache.

But I've discovered it was also changing the permissions on my cache folder to the wrong values each time I used it.
Thanks for pointing me in the right direction.